diff --git a/app/system/backend/sync_router.py b/app/system/backend/sync_router.py
index efeefbe..ff0fe62 100644
--- a/app/system/backend/sync_router.py
+++ b/app/system/backend/sync_router.py
@@ -345,12 +345,19 @@ async def sync_from_economic() -> Dict[str, Any]:
             # Extract email domain
             email_domain = email.split('@')[-1] if '@' in email else None
             
-            # Check if customer exists by economic_customer_number
+            # Check if customer exists by economic_customer_number OR CVR
             existing = execute_query(
                 "SELECT id FROM customers WHERE economic_customer_number = %s",
                 (customer_number,)
             )
             
+            # If not found by customer number, try CVR (to avoid duplicates)
+            if not existing and cvr:
+                existing = execute_query(
+                    "SELECT id FROM customers WHERE cvr_number = %s",
+                    (cvr,)
+                )
+            
             if existing:
                 # Update existing customer
                 update_query = """