diff --git a/packages/playwright-test/src/isomorphic/teleReceiver.ts b/packages/playwright-test/src/isomorphic/teleReceiver.ts
index 91edb7a3cf..7842855792 100644
--- a/packages/playwright-test/src/isomorphic/teleReceiver.ts
+++ b/packages/playwright-test/src/isomorphic/teleReceiver.ts
@@ -263,7 +263,7 @@ export class TeleReporterReceiver {
   }
 
   private _onStdIO(type: 'stdout' | 'stderr', testId: string | undefined, resultId: string | undefined, data: string, isBase64: boolean) {
-    const chunk = isBase64 ? Buffer.from(data, 'base64') : data;
+    const chunk = isBase64 ? ((globalThis as any).Buffer ? Buffer.from(data, 'base64') : atob(data)) : data;
     const test = testId ? this._tests.get(testId) : undefined;
     const result = test && resultId ? test.resultsMap.get(resultId) : undefined;
     if (type === 'stdout')
diff --git a/tests/playwright-test/ui-mode-test-output.spec.ts b/tests/playwright-test/ui-mode-test-output.spec.ts
index fc5ff0ece1..870a41fa28 100644
--- a/tests/playwright-test/ui-mode-test-output.spec.ts
+++ b/tests/playwright-test/ui-mode-test-output.spec.ts
@@ -56,3 +56,21 @@ test('should work after theme switch', async ({ runUITest, writeFiles }) => {
   await page.getByTitle('Run all').click();
   await expect(page.getByTestId('output')).toContainText(`Hello world 2`);
 });
+
+test('should print buffers', async ({ runUITest }) => {
+  const { page } = await runUITest({
+    'a.test.ts': `
+      import { test } from '@playwright/test';
+      import { PassThrough } from 'stream';
+      test('print', () => {
+        const writable = new PassThrough();
+        writable.pipe(process.stdout);
+        const red = Buffer.from('G1szMW1IRUxMTxtbMzlt', 'base64');
+        writable.write(red);
+      });
+    `,
+  });
+  await page.getByTitle('Toggle output').click();
+  await page.getByTitle('Run all').click();
+  await expect(page.getByTestId('output')).toContainText('HELLO', { timeout: 15000 });
+});