diff --git a/IRaCIS.Core.Application/Service/TrialSiteUser/TrialSiteService.cs b/IRaCIS.Core.Application/Service/TrialSiteUser/TrialSiteService.cs
index f131d5625..8ca70d2cb 100644
--- a/IRaCIS.Core.Application/Service/TrialSiteUser/TrialSiteService.cs
+++ b/IRaCIS.Core.Application/Service/TrialSiteUser/TrialSiteService.cs
@@ -169,6 +169,12 @@ namespace IRaCIS.Core.Application.Services
                 {
                     item.EnabledTime = DateTime.Now;
                 }
+
+                if (await _trialSiteRepository.AnyAsync(t => t.TrialSiteCode == item.TrialSiteCode && t.TrialId == item.TrialId))
+                {
+                    //---Code is not allowed to be repeated
+                    return ResponseOutput.NotOk(_localizer["TrialSite_CodeDuplicate"]);
+                }
             }
 
             await _trialSiteRepository.AddRangeAsync(addArray);