diff --git a/src/routes/files.test.ts b/src/routes/files.test.ts
index 230e090..5b45b37 100644
--- a/src/routes/files.test.ts
+++ b/src/routes/files.test.ts
@@ -70,11 +70,16 @@ describe('Files Route', () => {
       });
 
       expect(response.statusCode).toBe(200);
-      const body = JSON.parse(response.body) as { total: number };
+      const body = JSON.parse(response.body) as { total: number; files: unknown[] };
       expect(body.total).toBe(1);
+      expect(body.files).toHaveLength(1);
+      expect(body.files[0]).toMatchObject({
+        id: 'http://example.com/file1.wav',
+        filename: 'file1.wav',
+      });
       expect(prisma.file.findMany).toHaveBeenCalledWith(
         expect.objectContaining({
-          where: { entity: { id: 'http://example.com/collection/1' } },
+          where: { entity: { memberOf: 'http://example.com/collection/1' } },
         }),
       );
     });
diff --git a/src/routes/files.ts b/src/routes/files.ts
index 39e1720..f524690 100644
--- a/src/routes/files.ts
+++ b/src/routes/files.ts
@@ -37,7 +37,7 @@ const files: FastifyPluginAsync<FilesRouteOptions> = async (fastify, opts) => {
         const where: NonNullable<Parameters<typeof prisma.file.findMany>[0]>['where'] = {};
 
         if (memberOf) {
-          where.entity = { id: memberOf };
+          where.entity = { memberOf };
         }
 
         const [dbFiles, total] = await Promise.all([
diff --git a/src/test/integration.setup.ts b/src/test/integration.setup.ts
index b8bf42e..3ee71de 100644
--- a/src/test/integration.setup.ts
+++ b/src/test/integration.setup.ts
@@ -149,6 +149,31 @@ export async function seedTestData() {
     data: testEntities,
   });
 
+  const testFiles = [
+    {
+      id: 'http://example.com/entity/4',
+      filename: 'test-audio.wav',
+      mediaType: 'audio/wav',
+      size: BigInt(2048),
+      meta: {},
+      createdAt: new Date(),
+      updatedAt: new Date(),
+    },
+    {
+      id: 'http://example.com/entity/5',
+      filename: 'collection-metadata.csv',
+      mediaType: 'text/csv',
+      size: BigInt(512),
+      meta: {},
+      createdAt: new Date(),
+      updatedAt: new Date(),
+    },
+  ];
+
+  await prisma.file.createMany({
+    data: testFiles,
+  });
+
   await opensearch.indices.create({
     index: 'entities',
     body: {
diff --git a/src/test/integration.test.ts b/src/test/integration.test.ts
index 9d92426..4a42b8c 100644
--- a/src/test/integration.test.ts
+++ b/src/test/integration.test.ts
@@ -1,5 +1,5 @@
 import { afterAll, afterEach, beforeAll, beforeEach, describe, expect, it } from 'vitest';
-import type { AuthorisedEntity } from '../transformers/default.js';
+import type { AuthorisedEntity, AuthorisedFile } from '../transformers/default.js';
 import type { StandardErrorResponse } from '../utils/errors.js';
 import {
   cleanupTestData,
@@ -235,6 +235,77 @@ describe('Integration Tests', () => {
     });
   });
 
+  describe('GET /files', () => {
+    it('should return all files', async () => {
+      const app = getTestApp();
+
+      const response = await app.inject({
+        method: 'GET',
+        url: '/files',
+      });
+      const body = JSON.parse(response.body) as { total: number; files: AuthorisedFile[] };
+
+      expect(response.statusCode).toBe(200);
+      expect(body.total).toBe(2);
+      expect(body.files).toHaveLength(2);
+    });
+
+    it('should filter files by memberOf (Object parent)', async () => {
+      const app = getTestApp();
+
+      const response = await app.inject({
+        method: 'GET',
+        url: '/files',
+        query: {
+          memberOf: 'http://example.com/entity/2',
+        },
+      });
+      const body = JSON.parse(response.body) as { total: number; files: AuthorisedFile[] };
+
+      expect(response.statusCode).toBe(200);
+      expect(body.total).toBe(1);
+      expect(body.files).toHaveLength(1);
+      expect(body.files[0].id).toBe('http://example.com/entity/4');
+      expect(body.files[0].filename).toBe('test-audio.wav');
+    });
+
+    it('should filter files by memberOf (Collection parent)', async () => {
+      const app = getTestApp();
+
+      const response = await app.inject({
+        method: 'GET',
+        url: '/files',
+        query: {
+          memberOf: 'http://example.com/entity/1',
+        },
+      });
+      const body = JSON.parse(response.body) as { total: number; files: AuthorisedFile[] };
+
+      expect(response.statusCode).toBe(200);
+      expect(body.total).toBe(1);
+      expect(body.files).toHaveLength(1);
+      expect(body.files[0].id).toBe('http://example.com/entity/5');
+      expect(body.files[0].filename).toBe('collection-metadata.csv');
+    });
+
+    it('should return empty list when memberOf matches no entity', async () => {
+      const app = getTestApp();
+
+      const response = await app.inject({
+        method: 'GET',
+        url: '/files',
+        query: {
+          memberOf: 'http://example.com/entity/does-not-exist',
+        },
+      });
+      const body = JSON.parse(response.body) as { total: number; files: AuthorisedFile[] };
+
+      expect(response.statusCode).toBe(200);
+      expect(body.total).toBe(0);
+      expect(body.files).toHaveLength(0);
+    });
+  });
+
   describe('POST /search', () => {
     it('should perform basic search', async () => {
       const app = getTestApp();