diff --git a/src/main/java/edu/group5/app/model/user/UserService.java b/src/main/java/edu/group5/app/model/user/UserService.java
index 6bee483..e6439f1 100644
--- a/src/main/java/edu/group5/app/model/user/UserService.java
+++ b/src/main/java/edu/group5/app/model/user/UserService.java
@@ -51,7 +51,8 @@ public boolean registerUser(String role, String firstName, String lastName,
         firstName == null || firstName.trim().isEmpty() ||
         lastName == null || lastName.trim().isEmpty() ||
         email == null || email.trim().isEmpty() ||
-        passwordHash == null || passwordHash.trim().isEmpty()) {
+        passwordHash == null || passwordHash.trim().isEmpty() ||
+        this.getUserByEmail(email) != null) {
       return false;
     }
     User user;