diff --git a/erpnext/accounts/doctype/sales_invoice/pos.py b/erpnext/accounts/doctype/sales_invoice/pos.py
index 3e013f5..e2f99d6 100755
--- a/erpnext/accounts/doctype/sales_invoice/pos.py
+++ b/erpnext/accounts/doctype/sales_invoice/pos.py
@@ -451,6 +451,10 @@
 
 
 def add_customer(data):
+	customer = data.get('full_name') or data.get('customer')
+	if frappe.db.exists("Customer", customer.strip()):
+		return customer.strip()
+
 	customer_doc = frappe.new_doc('Customer')
 	customer_doc.customer_name = data.get('full_name') or data.get('customer')
 	customer_doc.customer_pos_id = data.get('customer_pos_id')