diff --git a/lib/tasks/2017_08_01_clean_assign_to.rake b/lib/tasks/2017_08_01_clean_assign_to.rake
new file mode 100644
index 000000000..fd407a956
--- /dev/null
+++ b/lib/tasks/2017_08_01_clean_assign_to.rake
@@ -0,0 +1,12 @@
+namespace :'2017_08_01_clean_assign_to' do
+  task clean: :environment do
+    duplicates = AssignTo.group(:gestionnaire_id, :procedure_id).count.select{ |_gestionnaire_id_procedure_id, count| count > 1 }.keys
+
+    duplicate_ids = duplicates.map { |gestionnaire_id, procedure_id| AssignTo.where(gestionnaire_id: gestionnaire_id, procedure_id: procedure_id).pluck(:id) }
+
+    duplicate_ids.each do |ids|
+      ids.pop
+      AssignTo.where(id: ids).destroy_all
+    end
+  end
+end