diff --git a/src/repositories/memberRepository.ts b/src/repositories/memberRepository.ts
new file mode 100644
index 0000000..c2ef56f
--- /dev/null
+++ b/src/repositories/memberRepository.ts
@@ -0,0 +1,68 @@
+import { getPrisma } from "../lib/db/prisma";
+import { MemberRegistration } from "@/domain/member/types";
+import { Prisma } from "@/generated/prisma/client";
+
+type CreateMembershipRegistrationResult =
+  | { ok: true }
+  | { ok: false; error: { type: "duplicate" | "database" } };
+
+export async function createMembershipRegistration(
+  registration: MemberRegistration,
+): Promise<CreateMembershipRegistrationResult> {
+  const memberData = toMemberCreateInput(registration);
+  try {
+    await getPrisma().member.create({ data: memberData });
+    return { ok: true };
+  } catch (error: unknown) {
+    if (error instanceof Prisma.PrismaClientKnownRequestError) {
+      if (error.code === "P2002") {
+        return { ok: false, error: { type: "duplicate" } };
+      }
+    }
+
+    return { ok: false, error: { type: "database" } };
+  }
+}
+
+function toMemberCreateInput(
+  registration: MemberRegistration,
+): Prisma.MemberCreateInput {
+  const memberData = {
+    // Unconditional fields
+    firstName: registration.firstName,
+    lastName: registration.lastName,
+    email: registration.email,
+    linuxSkillLevel: registration.linuxSkillLevel,
+    potentialInvolvement: registration.potentialInvolvement,
+    discordUsername: registration.discordUsername,
+
+    // Shared conditional field
+    isConditionalReturningMember: registration.isConditionalReturningMember,
+  };
+
+  // Non-shared conditional fields
+  const conditionalData =
+    registration.isConditionalReturningMember === true
+      ? {
+          upi: registration.upi,
+          studentId: registration.studentId,
+        }
+      : registration.isCurrentUoaStudent === true
+        ? {
+            faculty: registration.faculty,
+            programme: registration.programme,
+            yearLevel: registration.yearLevel,
+            upi: registration.upi,
+            studentId: registration.studentId,
+            isCurrentUoaStudent: registration.isCurrentUoaStudent,
+          }
+        : {
+            faculty: [],
+            primaryAffiliation: registration.primaryAffiliation,
+            nonUoaExcerpt: registration.nonUoaExcerpt,
+            nonUoaPitch: registration.nonUoaPitch,
+            isCurrentUoaStudent: registration.isCurrentUoaStudent,
+          };
+
+  return { ...memberData, ...conditionalData };
+}