diff --git a/app/models/epp/domain.rb b/app/models/epp/domain.rb
index 3f32ce6d5..3ac02c721 100644
--- a/app/models/epp/domain.rb
+++ b/app/models/epp/domain.rb
@@ -488,6 +488,15 @@ class Epp::Domain < Domain
 
     # at[:statuses] += at_add[:domain_statuses_attributes]
 
+    if registrant_id && registrant.code == frame.css('registrant')
+
+      throw :epp_error, {
+        code: '2305',
+        msg: I18n.t(:contact_already_associated_with_the_domain)
+      }
+
+    end
+
     if errors.empty? && verify &&
        Setting.request_confrimation_on_registrant_change_enabled &&
        frame.css('registrant').present? &&
diff --git a/config/locales/en.yml b/config/locales/en.yml
index db0ca37ce..27495c382 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -538,7 +538,7 @@ en:
   admin_menu: Admin
   domain_transfer_was_approved: 'Domain transfer was approved, associated contacts were: %{contacts} and registrant was %{registrant}'
   business_registry_service_not_available: "Business Registry service Ärireg is not available"
-  
+
   # DEPP
   activemodel:
     errors:
@@ -932,7 +932,8 @@ en:
   if_auth_info_is_left_empty_it_will_be_auto_generated: 'If auth info is left empty, it will be auto generated.'
   each_domain_name_must_end_with_colon_sign: 'Each domain name must end with colon (:) sign.'
   expiration_remind_subject: 'The %{name} domain has expired'
+  contact_already_associated_with_the_domain: 'Object association prohibits operation, contact already associated with the domain'
   add_reserved_domain: 'Add domain to reserved list'
   add_blocked_domain: 'Add domain to blocked list'
   edit_pw: 'Edit Pw'
-  optional: 'Optional'
\ No newline at end of file
+  optional: 'Optional'