diff --git a/app/models/registration.rb b/app/models/registration.rb
index 2f2d5c68..6b35e759 100644
--- a/app/models/registration.rb
+++ b/app/models/registration.rb
@@ -29,6 +29,7 @@ class Registration < ActiveRecord::Base
   validate :registration_limit_not_exceed, on: :create
 
   after_create :set_week, :subscribe_to_conference, :send_registration_mail
+  after_destroy :destroy_purchased_tickets
 
   def week
     created_at.strftime('%W').to_i
@@ -36,6 +37,13 @@ class Registration < ActiveRecord::Base
 
   private
 
+  def destroy_purchased_tickets
+    ticket_purchased = TicketPurchase.where(conference_id: conference_id)
+    unless ticket_purchased.empty?
+      ticket_purchased.destroy_all
+    end
+  end
+
   def subscribe_to_conference
     Subscription.create(conference_id: conference.id, user_id: user.id)
   end
diff --git a/spec/models/registration_spec.rb b/spec/models/registration_spec.rb
index 1bf9e88f..820ca0b9 100644
--- a/spec/models/registration_spec.rb
+++ b/spec/models/registration_spec.rb
@@ -22,4 +22,17 @@ describe 'Registration' do
       end
     end
   end
+  describe 'after destroy' do
+    it 'destroys purchased tickets' do
+      conference = build(:conference)
+      registration1 = build(:registration, conference: conference)
+      registration1.save
+      ticket_purchase = build(:ticket_purchase, conference: conference)
+      ticket_purchase.save
+      expect(conference.ticket_purchases.size).to be 1
+      registration1.destroy
+      expect(conference.registrations.size).to be 0
+      expect(conference.ticket_purchases.size).to be 0
+    end
+  end
 end