diff --git a/app/models/user.rb b/app/models/user.rb
index b64d0efd7..78bfc75f0 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -174,6 +174,7 @@ class User < Principal
   validates_format_of :login, :with => /\A[a-z0-9_\-@\.]*\z/i
   validates_length_of :login, :maximum => LOGIN_LENGTH_LIMIT
   validates_length_of :firstname, :maximum => 30
+  validates_length_of :lastname, :maximum => 30
   validates_format_of :mail, :with => /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i, :allow_blank => true
   validates_length_of :mail, :maximum => MAIL_LENGTH_LIMIT, :allow_nil => true
   validates_confirmation_of :password, :allow_nil => true