diff --git a/packages/amplify-ui-components/src/components/amplify-sign-up/amplify-sign-up.tsx b/packages/amplify-ui-components/src/components/amplify-sign-up/amplify-sign-up.tsx
index 055b39ea8a5..963bd293c79 100644
--- a/packages/amplify-ui-components/src/components/amplify-sign-up/amplify-sign-up.tsx
+++ b/packages/amplify-ui-components/src/components/amplify-sign-up/amplify-sign-up.tsx
@@ -133,6 +133,9 @@ export class AmplifySignUp {
         break;
     }
     try {
+      if (!this.signUpAttributes.username) {
+        throw new Error(Translations.EMPTY_USERNAME);
+      }
       if (this.signUpAttributes.username.indexOf(' ') >= 0) {
         throw new Error(Translations.USERNAME_REMOVE_WHITESPACE);
       }