diff --git a/doc/api/assert.md b/doc/api/assert.md
index 5f9a99c9bf97ed..e97134832d8677 100644
--- a/doc/api/assert.md
+++ b/doc/api/assert.md
@@ -375,6 +375,8 @@ argument in callbacks.
 ```js
 const assert = require('assert');
 
+assert.ifError(null);
+// OK
 assert.ifError(0);
 // OK
 assert.ifError(1);