diff --git a/speech/system-test/recognize.test.js b/speech/system-test/recognize.test.js
index 7da66d5031..870caeebfa 100644
--- a/speech/system-test/recognize.test.js
+++ b/speech/system-test/recognize.test.js
@@ -21,7 +21,7 @@ describe('speech:recognize', function () {
     recognizeExample.main(
       path.join(__dirname, '../resources/audio.raw'),
       function (err, result) {
-        assert(!err);
+        assert.ifError(err);
         assert(result);
         assert(Array.isArray(result.results));
         assert(result.results.length === 1);
diff --git a/speech/system-test/recognize_streaming.test.js b/speech/system-test/recognize_streaming.test.js
index 0d008d0c1c..b155cf426e 100644
--- a/speech/system-test/recognize_streaming.test.js
+++ b/speech/system-test/recognize_streaming.test.js
@@ -22,7 +22,7 @@ describe('speech:recognize_streaming', function () {
       path.join(__dirname, '../resources/audio.raw'),
       process.env.SPEECH_API_HOST || 'speech.googleapis.com',
       function (err, results) {
-        assert(!err);
+        assert.ifError(err);
         assert(results);
         assert(results.length === 3);
         assert(results[0].results);