diff --git a/packages/core/db/migrations/0004_birthday_can_be_null.sql b/packages/core/db/migrations/0004_birthday_can_be_null.sql
new file mode 100644
index 0000000..5b328ba
--- /dev/null
+++ b/packages/core/db/migrations/0004_birthday_can_be_null.sql
@@ -0,0 +1 @@
+ALTER TABLE "users" ALTER COLUMN "birthday" DROP NOT NULL;
\ No newline at end of file
diff --git a/packages/core/db/migrations/meta/0003_snapshot.json b/packages/core/db/migrations/meta/0003_snapshot.json
index 19921f8..762ffd9 100644
--- a/packages/core/db/migrations/meta/0003_snapshot.json
+++ b/packages/core/db/migrations/meta/0003_snapshot.json
@@ -39,14 +39,8 @@
           "name": "iceBreakerThreads_user_id_team_id_users_id_team_id_fk",
           "tableFrom": "iceBreakerThreads",
           "tableTo": "users",
-          "columnsFrom": [
-            "user_id",
-            "team_id"
-          ],
-          "columnsTo": [
-            "id",
-            "team_id"
-          ],
+          "columnsFrom": ["user_id", "team_id"],
+          "columnsTo": ["id", "team_id"],
           "onDelete": "cascade",
           "onUpdate": "no action"
         }
@@ -95,14 +89,8 @@
           "name": "presentIdeas_user_id_team_id_users_id_team_id_fk",
           "tableFrom": "presentIdeas",
           "tableTo": "users",
-          "columnsFrom": [
-            "user_id",
-            "team_id"
-          ],
-          "columnsTo": [
-            "id",
-            "team_id"
-          ],
+          "columnsFrom": ["user_id", "team_id"],
+          "columnsTo": ["id", "team_id"],
           "onDelete": "cascade",
           "onUpdate": "no action"
         },
@@ -110,14 +98,8 @@
           "name": "presentIdeas_birthday_person_team_id_users_id_team_id_fk",
           "tableFrom": "presentIdeas",
           "tableTo": "users",
-          "columnsFrom": [
-            "birthday_person",
-            "team_id"
-          ],
-          "columnsTo": [
-            "id",
-            "team_id"
-          ],
+          "columnsFrom": ["birthday_person", "team_id"],
+          "columnsTo": ["id", "team_id"],
           "onDelete": "cascade",
           "onUpdate": "no action"
         }
@@ -175,10 +157,7 @@
       "compositePrimaryKeys": {
         "users_id_team_id": {
           "name": "users_id_team_id",
-          "columns": [
-            "id",
-            "team_id"
-          ]
+          "columns": ["id", "team_id"]
         }
       },
       "uniqueConstraints": {}
@@ -191,4 +170,4 @@
     "tables": {},
     "columns": {}
   }
-}
\ No newline at end of file
+}
diff --git a/packages/core/db/migrations/meta/0004_snapshot.json b/packages/core/db/migrations/meta/0004_snapshot.json
new file mode 100644
index 0000000..042b5eb
--- /dev/null
+++ b/packages/core/db/migrations/meta/0004_snapshot.json
@@ -0,0 +1,194 @@
+{
+  "version": "5",
+  "dialect": "pg",
+  "id": "f4d596d1-e02b-4c39-98c3-5a48f49b8c65",
+  "prevId": "3ba6727b-d01d-4de2-a788-d1cdaa365084",
+  "tables": {
+    "iceBreakerThreads": {
+      "name": "iceBreakerThreads",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "serial",
+          "primaryKey": true,
+          "notNull": true
+        },
+        "team_id": {
+          "name": "team_id",
+          "type": "varchar",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "user_id": {
+          "name": "user_id",
+          "type": "varchar",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "thread_id": {
+          "name": "thread_id",
+          "type": "varchar",
+          "primaryKey": false,
+          "notNull": true
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {
+        "iceBreakerThreads_user_id_team_id_users_id_team_id_fk": {
+          "name": "iceBreakerThreads_user_id_team_id_users_id_team_id_fk",
+          "tableFrom": "iceBreakerThreads",
+          "tableTo": "users",
+          "columnsFrom": [
+            "user_id",
+            "team_id"
+          ],
+          "columnsTo": [
+            "id",
+            "team_id"
+          ],
+          "onDelete": "cascade",
+          "onUpdate": "no action"
+        }
+      },
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {}
+    },
+    "presentIdeas": {
+      "name": "presentIdeas",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "serial",
+          "primaryKey": true,
+          "notNull": true
+        },
+        "team_id": {
+          "name": "team_id",
+          "type": "varchar",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "birthday_person": {
+          "name": "birthday_person",
+          "type": "varchar",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "user_id": {
+          "name": "user_id",
+          "type": "varchar",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "present_idea": {
+          "name": "present_idea",
+          "type": "varchar",
+          "primaryKey": false,
+          "notNull": true
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {
+        "presentIdeas_user_id_team_id_users_id_team_id_fk": {
+          "name": "presentIdeas_user_id_team_id_users_id_team_id_fk",
+          "tableFrom": "presentIdeas",
+          "tableTo": "users",
+          "columnsFrom": [
+            "user_id",
+            "team_id"
+          ],
+          "columnsTo": [
+            "id",
+            "team_id"
+          ],
+          "onDelete": "cascade",
+          "onUpdate": "no action"
+        },
+        "presentIdeas_birthday_person_team_id_users_id_team_id_fk": {
+          "name": "presentIdeas_birthday_person_team_id_users_id_team_id_fk",
+          "tableFrom": "presentIdeas",
+          "tableTo": "users",
+          "columnsFrom": [
+            "birthday_person",
+            "team_id"
+          ],
+          "columnsTo": [
+            "id",
+            "team_id"
+          ],
+          "onDelete": "cascade",
+          "onUpdate": "no action"
+        }
+      },
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {}
+    },
+    "testItems": {
+      "name": "testItems",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "varchar",
+          "primaryKey": true,
+          "notNull": true
+        },
+        "payload": {
+          "name": "payload",
+          "type": "varchar",
+          "primaryKey": false,
+          "notNull": true
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {}
+    },
+    "users": {
+      "name": "users",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "varchar",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "team_id": {
+          "name": "team_id",
+          "type": "varchar",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "birthday": {
+          "name": "birthday",
+          "type": "date",
+          "primaryKey": false,
+          "notNull": false
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {
+        "users_id_team_id": {
+          "name": "users_id_team_id",
+          "columns": [
+            "id",
+            "team_id"
+          ]
+        }
+      },
+      "uniqueConstraints": {}
+    }
+  },
+  "enums": {},
+  "schemas": {},
+  "_meta": {
+    "schemas": {},
+    "tables": {},
+    "columns": {}
+  }
+}
\ No newline at end of file
diff --git a/packages/core/db/migrations/meta/_journal.json b/packages/core/db/migrations/meta/_journal.json
index e1889bc..16d6c46 100644
--- a/packages/core/db/migrations/meta/_journal.json
+++ b/packages/core/db/migrations/meta/_journal.json
@@ -29,6 +29,13 @@
       "when": 1699369077670,
       "tag": "0003_present_ideas",
       "breakpoints": true
+    },
+    {
+      "idx": 4,
+      "version": "5",
+      "when": 1699455923273,
+      "tag": "0004_birthday_can_be_null",
+      "breakpoints": true
     }
   ]
 }
diff --git a/packages/core/db/queries/getBirthdays.ts b/packages/core/db/queries/getBirthdays.ts
index c3b81a5..36135cd 100644
--- a/packages/core/db/queries/getBirthdays.ts
+++ b/packages/core/db/queries/getBirthdays.ts
@@ -1,5 +1,5 @@
 import type { Dayjs } from "dayjs";
-import { and, or, sql } from "drizzle-orm";
+import { and, isNull, or, sql } from "drizzle-orm";
 
 import { db } from "@/db/index";
 import { users } from "@/db/schema";
@@ -39,3 +39,8 @@ export const getBirthdays = async (date: Dayjs) =>
       sql`EXTRACT('DAY' FROM ${users.birthday}) = ${date.date()}`,
     ),
   });
+
+export const getUsersWhoseBirthdayIsMissing = async () =>
+  db.query.users.findMany({
+    where: isNull(users.birthday),
+  });
diff --git a/packages/core/db/queries/saveBirthday.ts b/packages/core/db/queries/saveBirthday.ts
index 6550ded..449fcb5 100644
--- a/packages/core/db/queries/saveBirthday.ts
+++ b/packages/core/db/queries/saveBirthday.ts
@@ -9,21 +9,23 @@ import { users } from "@/db/schema";
 type Args = {
   user: string;
   teamId: string;
-  birthday: string;
+  birthday: string | null;
 };
 
 export const saveBirthday = async ({ birthday, teamId, user }: Args) => {
+  const birthdayDate = birthday ? dayjs.utc(birthday).toDate() : null;
+
   await db
     .insert(users)
     .values({
       id: user,
       teamId,
-      birthday: dayjs.utc(birthday).toDate(),
+      birthday: birthdayDate,
     })
     .onConflictDoUpdate({
       target: [users.id, users.teamId],
       set: {
-        birthday: dayjs.utc(birthday).toDate(),
+        birthday: birthdayDate,
       },
     });
 };
diff --git a/packages/core/db/schema.ts b/packages/core/db/schema.ts
index 7b9b99c..1a6e828 100644
--- a/packages/core/db/schema.ts
+++ b/packages/core/db/schema.ts
@@ -12,7 +12,7 @@ export const users = pgTable(
   {
     id: varchar("id").notNull(),
     teamId: varchar("team_id").notNull(),
-    birthday: date("birthday", { mode: "date" }).notNull(),
+    birthday: date("birthday", { mode: "date" }),
   },
   (t) => ({
     pk: primaryKey(t.id, t.teamId),
diff --git a/packages/functions/cron/daily.ts b/packages/functions/cron/daily.ts
index f1e2813..906caf2 100644
--- a/packages/functions/cron/daily.ts
+++ b/packages/functions/cron/daily.ts
@@ -3,10 +3,26 @@ import utc from "dayjs/plugin/utc";
 
 dayjs.extend(utc);
 
-import { getBirthdays } from "@/db/queries/getBirthdays";
+import {
+  getBirthdays,
+  getUsersWhoseBirthdayIsMissing,
+} from "@/db/queries/getBirthdays";
 import { publishEvent } from "@/utils/eventBridge/publishEvent";
 import { cronHandler } from "@/utils/lambda/cronHandler";
 
+const sendReminderWhoseBirthdayIsMissing = async (eventId?: string) => {
+  const users = await getUsersWhoseBirthdayIsMissing();
+
+  await Promise.all(
+    users.map((user) =>
+      publishEvent("askBirthday", {
+        user: user.id,
+        eventId,
+      }),
+    ),
+  );
+};
+
 export const handler = cronHandler(async (eventId?: string) => {
   try {
     const today = dayjs().utc().startOf("day");
@@ -23,6 +39,8 @@ export const handler = cronHandler(async (eventId?: string) => {
       ),
     );
 
+    await sendReminderWhoseBirthdayIsMissing(eventId);
+
     return {
       users,
       message: users.length ? "Sent present ideas requests" : "No birthdays",
diff --git a/packages/functions/events/askBirthday.ts b/packages/functions/events/askBirthday.ts
index 1b845aa..cfbb70b 100644
--- a/packages/functions/events/askBirthday.ts
+++ b/packages/functions/events/askBirthday.ts
@@ -1,3 +1,4 @@
+import { saveBirthday } from "@/db/queries/saveBirthday";
 import {
   constructAskBirthdayMessage,
   constructAskBirthdayMessageReplacement,
@@ -10,9 +11,9 @@ export const handler = handleEvent(
   "askBirthday",
   async ({ user, eventId, responseUrl }) => {
     try {
-      const userInfo = await getUserInfo(user);
+      const { user: userInfo } = await getUserInfo(user);
 
-      if (!userInfo.user || userInfo.user.is_bot) {
+      if (!userInfo || userInfo.is_bot || !userInfo.team_id) {
         return;
       }
 
@@ -20,7 +21,7 @@ export const handler = handleEvent(
 
       const payload = {
         user,
-        name: userInfo.user.profile?.first_name || userInfo.user.name || "",
+        name: userInfo.profile?.first_name || userInfo.name || "",
         eventId,
       };
 
@@ -35,6 +36,12 @@ export const handler = handleEvent(
         return;
       }
 
+      await saveBirthday({
+        birthday: null,
+        teamId: userInfo.team_id,
+        user,
+      });
+
       await app.client.chat.postMessage(constructAskBirthdayMessage(payload));
     } catch (error) {
       console.error("Error processing askBirthday event: ", error);
diff --git a/tests/integration/askBirthday.test.ts b/tests/integration/askBirthday.test.ts
index 0cbf7bb..f0d96a2 100644
--- a/tests/integration/askBirthday.test.ts
+++ b/tests/integration/askBirthday.test.ts
@@ -7,6 +7,7 @@ import { constructBirthdayConfirmedMessage } from "@/services/slack/constructBir
 import { constructConfirmBirthdayMessage } from "@/services/slack/constructConfirmBirthdayMessage";
 import { pollInterval, timeout, waitTimeout } from "@/testUtils/constants";
 import { deleteLastDm } from "@/testUtils/integration/deleteLastDm";
+import { sendCronEvent } from "@/testUtils/integration/sendCronEvent";
 import { sendSlackInteraction } from "@/testUtils/integration/sendSlackInteraction";
 import { app } from "@/testUtils/integration/testSlackApp";
 import { waitForDm } from "@/testUtils/integration/waitForDm";
@@ -207,4 +208,29 @@ describe("Slack interactions", () => {
     },
     timeout,
   );
+
+  it(
+    "Should ask for birthday again when birthday is null",
+    async () => {
+      const eventId = "AB5_" + Date.now().toString();
+
+      await testDb.insert(users).values([
+        {
+          id: import.meta.env.VITE_SLACK_USER_ID,
+          teamId: import.meta.env.VITE_SLACK_TEAM_ID,
+          birthday: null,
+        },
+      ]);
+
+      await sendCronEvent("daily", eventId);
+
+      const message = await waitForDm(eventId);
+
+      expect(
+        message.blocks?.[1].accessory?.type,
+        "Message doesn't have datepicker",
+      ).toBe("datepicker");
+    },
+    timeout,
+  );
 });
diff --git a/tests/unit/askBirthday.test.ts b/tests/unit/askBirthday.test.ts
index 459d728..a58abf3 100644
--- a/tests/unit/askBirthday.test.ts
+++ b/tests/unit/askBirthday.test.ts
@@ -1,26 +1,44 @@
 import "@/testUtils/unit/mockSlackApp";
+import "@/testUtils/unit/mockDb";
 
+import dayjs from "dayjs";
+import utc from "dayjs/plugin/utc";
 import type { Mock } from "vitest";
-import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import {
+  afterEach,
+  beforeAll,
+  beforeEach,
+  describe,
+  expect,
+  it,
+  vi,
+} from "vitest";
 
+import { getUsersWhoseBirthdayIsMissing } from "@/db/queries/getBirthdays";
+import { users } from "@/db/schema";
 import type { Events } from "@/events";
 import { handler } from "@/functions/events/askBirthday";
 import { constructAskBirthdayMessage } from "@/services/slack/constructAskBirthdayMessage";
 import { createSlackApp } from "@/services/slack/createSlackApp";
 import { getUserInfo } from "@/services/slack/getUserInfo";
+import { testDb } from "@/testUtils/testDb";
 import { sendMockSqsMessage } from "@/testUtils/unit/sendMockSqsMessage";
 
+dayjs.extend(utc);
+
 const constants = vi.hoisted(() => ({
   otherBotUserId: "B999",
   userId: "U001",
   userName: "Foo",
   eventId: "E001",
+  team_id: "T001",
 }));
 
 vi.mock("@/services/slack/getUserInfo", async () => ({
   getUserInfo: vi.fn().mockResolvedValue({
     user: {
       is_bot: false,
+      team_id: constants.team_id,
       profile: {
         first_name: constants.userName,
       },
@@ -37,8 +55,9 @@ describe("Member joined channel", () => {
     createSlackAppMock = createSlackApp as Mock;
   });
 
-  afterEach(() => {
+  afterEach(async () => {
     vi.clearAllMocks();
+    await testDb.delete(users);
   });
 
   it("Should not do anything if user is a bot", async () => {
@@ -81,3 +100,38 @@ describe("Member joined channel", () => {
     );
   });
 });
+
+describe("getUsersWhoseBirthdayIsMissing", () => {
+  beforeAll(async () => {
+    await testDb.delete(users);
+  });
+  afterEach(async () => {
+    vi.clearAllMocks();
+    await testDb.delete(users);
+  });
+
+  const mockUser = {
+    birthday: null,
+    id: constants.userId,
+    teamId: constants.team_id,
+  };
+
+  it("should return with the mock user", async () => {
+    await testDb.insert(users).values([mockUser]);
+    const result = await getUsersWhoseBirthdayIsMissing();
+
+    expect(result).toEqual([mockUser]);
+  });
+
+  it("shouldn't find any users", async () => {
+    const mockUserWithBirthday = {
+      ...mockUser,
+      birthday: dayjs.utc().toDate(),
+    };
+
+    await testDb.insert(users).values([mockUserWithBirthday]);
+    const result = await getUsersWhoseBirthdayIsMissing();
+
+    expect(result).toEqual([]);
+  });
+});