diff --git a/app/models/course.rb b/app/models/course.rb
index ec1afd611..143358abe 100644
--- a/app/models/course.rb
+++ b/app/models/course.rb
@@ -18,7 +18,7 @@ class Course < ActiveRecord::Base
            :conditions => "#{Principal.table_name}.type='Group' OR (#{Principal.table_name}.type='User' AND #{Principal.table_name}.status=#{Principal::STATUS_ACTIVE})"
   has_many :principals, :through => :member_principals, :source => :principal
   has_many :users, :through => :members
-  has_many :org_courses
+  has_many :org_courses, :dependent => :destroy
   has_many :organizations, :through => :org_courses
   # has_many :homeworks, :through => :homework_for_courses, :source => :bid, :dependent => :destroy
   has_many :journals_for_messages, :as => :jour, :dependent => :destroy
diff --git a/app/models/organization.rb b/app/models/organization.rb
index d3755b5ee..a35f68c26 100644
--- a/app/models/organization.rb
+++ b/app/models/organization.rb
@@ -5,7 +5,7 @@ class Organization < ActiveRecord::Base
   has_many :projects,:through => :org_projects
   has_many :courses, :through => :org_courses
   has_many :org_document_comments, :dependent => :destroy
-  has_many :org_courses
+  has_many :org_courses, :dependent => :destroy
   has_many :users, :through => :org_members
   validates_uniqueness_of :name
   after_create :save_as_org_activity