diff --git a/mailing_lists/app/models/mailing_list.rb b/mailing_lists/app/models/mailing_list.rb
index 8b65cbfd4..5795b942b 100644
--- a/mailing_lists/app/models/mailing_list.rb
+++ b/mailing_lists/app/models/mailing_list.rb
@@ -22,7 +22,7 @@ class MailingList < ActiveRecord::Base
   belongs_to :admin, :class_name => 'User', :foreign_key => 'admin_id'
   has_many :messages, :class_name => 'MailingMessage', :dependent => :delete_all
       
-  validates_presence_of :name, :description, :password
+  validates_presence_of :name, :description, :password, :admin_id
   validates_confirmation_of :password
   validates_format_of :name, :with => /^[a-z0-9\-]+$/i
   
diff --git a/mailing_lists/app/models/mailing_message.rb b/mailing_lists/app/models/mailing_message.rb
index b1969f3bd..dd8d9a709 100644
--- a/mailing_lists/app/models/mailing_message.rb
+++ b/mailing_lists/app/models/mailing_message.rb
@@ -18,4 +18,6 @@
 class MailingMessage < ActiveRecord::Base
   belongs_to :mailing_list
   acts_as_tree :order => 'sent_on'
+  
+  validates_uniqueness_of :messageid, :scope => :mailing_list_id
 end