diff --git a/register.php b/register.php
index 9bee1db..bc1196a 100644
--- a/register.php
+++ b/register.php
@@ -49,7 +49,7 @@ if (POST_SUBMITTED != '') {
         
     // Check if username is valid (length, authorized characters)
     } elseif (!$userservice->isValidUsername($posteduser)) {
-        $tplVars['error'] = T_('This username is not valid (too long, forbidden characters...), please make another choice.');        
+        $tplVars['error'] = T_('This username is not valid (too short, too long, forbidden characters...), please make another choice.');        
     
     // Check if e-mail address is valid
     } elseif (!$userservice->isValidEmail(POST_MAIL)) {
diff --git a/services/userservice.php b/services/userservice.php
index ad79d34..fa0d5c9 100644
--- a/services/userservice.php
+++ b/services/userservice.php
@@ -445,7 +445,9 @@ class UserService {
 	}
 
 	function isValidUsername($username) {
-		if (strlen($username) > 24) {
+		if (strlen($username) < 4) {
+			return false;
+		}elseif (strlen($username) > 24) {
 			// too long usernames are cut by database and may cause bugs when compared
 			return false;
 		} elseif (preg_match('/(\W)/', $username) > 0) {