diff --git a/erpnext/accounts/doctype/pricing_rule/pricing_rule.py b/erpnext/accounts/doctype/pricing_rule/pricing_rule.py
index 5fd933b3d98..1d8d9dbcef5 100644
--- a/erpnext/accounts/doctype/pricing_rule/pricing_rule.py
+++ b/erpnext/accounts/doctype/pricing_rule/pricing_rule.py
@@ -34,6 +34,9 @@ class PricingRule(Document):
 
 	def validate_duplicate_apply_on(self):
 		field = apply_on_dict.get(self.apply_on)
+		if not field:
+			return False
+
 		values = [d.get(frappe.scrub(self.apply_on)) for d in self.get(field)]
 
 		if len(values) != len(set(values)):
@@ -419,4 +422,4 @@ def get_item_uoms(doctype, txt, searchfield, start, page_len, filters):
 
 	return frappe.get_all('UOM Conversion Detail',
 		filters = {'parent': ('in', items), 'uom': ("like", "{0}%".format(txt))},
-		fields = ["distinct uom"], as_list=1)
\ No newline at end of file
+		fields = ["distinct uom"], as_list=1)