diff --git a/src/client/network.ts b/src/client/network.ts
index 44c96dc726..35b61a1e80 100644
--- a/src/client/network.ts
+++ b/src/client/network.ts
@@ -113,9 +113,6 @@ export class Request extends ChannelOwner<channels.RequestChannel, channels.Requ
       return null;
 
     const contentType = this.headers()['content-type'];
-    if (!contentType)
-      return null;
-
     if (contentType === 'application/x-www-form-urlencoded') {
       const entries: Record<string, string> = {};
       const parsed = new URLSearchParams(postData);
@@ -124,7 +121,11 @@ export class Request extends ChannelOwner<channels.RequestChannel, channels.Requ
       return entries;
     }
 
-    return JSON.parse(postData);
+    try {
+      return JSON.parse(postData);
+    } catch (e) {
+      throw new Error('POST data is not a valid JSON object: ' + postData);
+    }
   }
 
   headers(): Headers {
diff --git a/test/page-wait-for-request.spec.ts b/test/page-wait-for-request.spec.ts
index 0b89bf1317..de7a93bb44 100644
--- a/test/page-wait-for-request.spec.ts
+++ b/test/page-wait-for-request.spec.ts
@@ -118,3 +118,40 @@ it('should return correct postData buffer for utf-8 body', async ({page, server}
   expect(request.postDataBuffer().equals(Buffer.from(JSON.stringify(value), 'utf-8'))).toBe(true);
   expect(request.postDataJSON()).toBe(value);
 });
+
+it('should return post data w/o content-type', async ({page, server}) => {
+  await page.goto(server.EMPTY_PAGE);
+  const [request] = await Promise.all([
+    page.waitForRequest('**'),
+    page.evaluate(({url}) => {
+      const request = new Request(url, {
+        method: 'POST',
+        body: JSON.stringify({ value: 42 }),
+      });
+      request.headers.set('content-type', '');
+      return fetch(request);
+    }, {url: server.PREFIX + '/title.html'})
+  ]);
+  expect(request.postDataJSON()).toEqual({ value: 42 });
+});
+
+it('should throw on invalid JSON in post data', async ({page, server}) => {
+  await page.goto(server.EMPTY_PAGE);
+  const [request] = await Promise.all([
+    page.waitForRequest('**'),
+    page.evaluate(({url}) => {
+      const request = new Request(url, {
+        method: 'POST',
+        body: '<not a json>',
+      });
+      return fetch(request);
+    }, {url: server.PREFIX + '/title.html'})
+  ]);
+  let error;
+  try {
+    request.postDataJSON();
+  } catch (e) {
+    error = e;
+  }
+  expect(error.message).toContain('POST data is not a valid JSON object: <not a json>');
+});