diff --git a/register.php b/register.php
index f89bc83..0294eba 100644
--- a/register.php
+++ b/register.php
@@ -10,6 +10,7 @@ require_once 'core/config.php';
 
 $getitstarted = new PartyStarter;
 $getitstarted->header();
+$usernamespecialchar = false;
 $passwordconfirmiswrong = false;
 $passwordistooshort = false;
 $user = new User($con, 0);
@@ -24,6 +25,12 @@ if(isset($_POST['submit'])) {
     }
 </script>';
 	$user = new User($con, $user->getID($con, $username));
+    if(preg_match('/^[a-zA-Z0-9]+$/', $username) == 0) {
+        $usernamespecialchar = true;
+    } else {
+        $usernamespecialchar = false;
+    }
+
 	if ($password == $passwordconfirm) {
       $passwordconfirmiswrong = false;
 	} else {
@@ -35,7 +42,7 @@ if(isset($_POST['submit'])) {
 	} else {
      $passwordistooshort = false;
 	}
-	if ($passwordistooshort == false && $passwordconfirmiswrong == false) {
+	if ($passwordistooshort == false && $passwordconfirmiswrong == false && $usernamespecialchar == false) {
 			$password = password_hash($password, PASSWORD_BCRYPT);
 			$query = $con->prepare('SELECT COUNT(*) FROM users WHERE username=:username');
 			$query->bindParam(':username', $username);
@@ -82,7 +89,7 @@ $thefunfact = json_decode($result);
       <h3 class="card-header">Registration</h3>
       <div class="card-body">
        <label class="col-form-label col-form-label-sm mt-4 username " for="inputSmall">Username</label>
-       <input class="<?php if($userexists == true) { echo "form-control is-invalid"; } else { echo "form-control form-control-sm"; }	?>" type="text" placeholder="Your username" id="inputSmall" for="inputValid" name="username"> <?php if($userexists == true) { echo '<div class="invalid-feedback" bis_skin_checked="1">Username is already taken.</div>'; } ?> 
+       <input class="<?php if($userexists == true || $usernamespecialchar == true) { echo "form-control is-invalid"; } else { echo "form-control form-control-sm"; }	?>" type="text" placeholder="Your username" id="inputSmall" for="inputValid" name="username"> <?php if($userexists == true) { echo '<div class="invalid-feedback" bis_skin_checked="1">Username is already taken.</div>'; } elseif($usernamespecialchar == true) { echo '<div class="invalid-feedback" bis_skin_checked="1">Special characters are not allowed.</div>'; } ?> 
         <label class="col-form-label col-form-label-sm mt-4 password " for="inputSmall">Password</label>
        <input class="<?php if($passwordconfirmiswrong == true) { echo "form-control is-invalid"; } else { echo "form-control form-control-sm"; }	?>" type="password" placeholder="Your password (Minmum 8 characters)" id="inputSmall" name="pass"> <?php if($passwordconfirmiswrong == true) { echo '<div class="invalid-feedback" bis_skin_checked="1">Password Confirmation field is invalid.</div>'; } else if ($passwordistooshort == true) { echo '<div class="invalid-feedback" bis_skin_checked="1">Password is too short. (8 Characters minmum)</div>'; } ?> <label class="col-form-label col-form-label-sm mt-4 passwordconfirm" for="inputSmall">Password Confirmation</label>
        <input class="form-control form-control-sm" type="password" placeholder="Enter your password again" id="inputSmall" name="passconfirm">