diff --git a/backend/src/db/migrations/20240405000045_org-memberships-unique-constraint.ts b/backend/src/db/migrations/20240405000045_org-memberships-unique-constraint.ts
index bbe484c7d..9a342d542 100644
--- a/backend/src/db/migrations/20240405000045_org-memberships-unique-constraint.ts
+++ b/backend/src/db/migrations/20240405000045_org-memberships-unique-constraint.ts
@@ -1,8 +1,104 @@
 import { Knex } from "knex";
+import { z } from "zod";
 
-import { TableName } from "../schemas";
+import { TableName, TOrgMemberships } from "../schemas";
+
+const validateOrgMembership = (membershipToValidate: TOrgMemberships, firstMembership: TOrgMemberships) => {
+  const firstOrgId = firstMembership.orgId;
+  const firstUserId = firstMembership.userId;
+
+  if (membershipToValidate.id === firstMembership.id) {
+    return;
+  }
+
+  if (membershipToValidate.inviteEmail !== firstMembership.inviteEmail) {
+    throw new Error(`Invite emails are different for the same userId and orgId: ${firstUserId}, ${firstOrgId}`);
+  }
+  if (membershipToValidate.orgId !== firstMembership.orgId) {
+    throw new Error(`OrgIds are different for the same userId and orgId: ${firstUserId}, ${firstOrgId}`);
+  }
+  if (membershipToValidate.role !== firstMembership.role) {
+    throw new Error(`Roles are different for the same userId and orgId: ${firstUserId}, ${firstOrgId}`);
+  }
+  if (membershipToValidate.roleId !== firstMembership.roleId) {
+    throw new Error(`RoleIds are different for the same userId and orgId: ${firstUserId}, ${firstOrgId}`);
+  }
+  if (membershipToValidate.status !== firstMembership.status) {
+    throw new Error(`Statuses are different for the same userId and orgId: ${firstUserId}, ${firstOrgId}`);
+  }
+  if (membershipToValidate.userId !== firstMembership.userId) {
+    throw new Error(`UserIds are different for the same userId and orgId: ${firstUserId}, ${firstOrgId}`);
+  }
+};
 
 export async function up(knex: Knex): Promise<void> {
+  const RowSchema = z.object({
+    userId: z.string(),
+    orgId: z.string(),
+    cnt: z.string()
+  });
+
+  // Transactional find and delete duplicate rows
+  await knex.transaction(async (tx) => {
+    const duplicateRows = await tx(TableName.OrgMembership)
+      .select("userId", "orgId") // Select the userId and orgId so we can group by them
+      .count("* as cnt") // Count the number of rows for each userId and orgId, so we can make sure there are more than 1 row (a duplicate)
+      .groupBy("userId", "orgId")
+      .havingRaw("count(*) > ?", [1]); // Using havingRaw for direct SQL expressions
+
+    // Parse the rows to ensure they are in the correct format, and for type safety
+    const parsedRows = RowSchema.array().parse(duplicateRows);
+
+    // For each of the duplicate rows, loop through and find the actual memberships to delete
+    for (const row of parsedRows) {
+      const count = Number(row.cnt);
+
+      // An extra check to ensure that the count is actually a number, and the number is greater than 2
+      if (typeof count !== "number" || count < 2) {
+        // eslint-disable-next-line no-continue
+        continue;
+      }
+
+      // Find all the organization memberships that have the same userId and orgId
+      // eslint-disable-next-line no-await-in-loop
+      const rowsToDelete = await tx(TableName.OrgMembership).where({
+        userId: row.userId,
+        orgId: row.orgId
+      });
+
+      // Ensure that all the rows have exactly the same value, except id, createdAt, updatedAt
+      for (const rowToDelete of rowsToDelete) {
+        validateOrgMembership(rowToDelete, rowsToDelete[0]);
+      }
+
+      // Find the row with the latest createdAt, which we will keep
+
+      let lowestCreatedAt: number | null = null;
+      let latestCreatedRow: TOrgMemberships | null = null;
+
+      for (const rowToDelete of rowsToDelete) {
+        if (lowestCreatedAt === null || rowToDelete.createdAt.getTime() < lowestCreatedAt) {
+          lowestCreatedAt = rowToDelete.createdAt.getTime();
+          latestCreatedRow = rowToDelete;
+        }
+      }
+      if (!latestCreatedRow) {
+        throw new Error("Failed to find last created membership");
+      }
+
+      // Filter out the latest row from the rows to delete
+      const membershipIdsToDelete = rowsToDelete.map((r) => r.id).filter((id) => id !== latestCreatedRow!.id);
+
+      // eslint-disable-next-line no-await-in-loop
+      const numberOfRowsDeleted = await tx(TableName.OrgMembership).whereIn("id", membershipIdsToDelete).delete();
+
+      // eslint-disable-next-line no-console
+      console.log(
+        `Deleted ${numberOfRowsDeleted} duplicate organization memberships for ${row.userId} and ${row.orgId}`
+      );
+    }
+  });
+
   await knex.schema.alterTable(TableName.OrgMembership, (table) => {
     table.unique(["userId", "orgId"]);
   });