diff --git a/erpnext/manufacturing/doctype/bom/bom.py b/erpnext/manufacturing/doctype/bom/bom.py
index 6bda802..b949a0f 100644
--- a/erpnext/manufacturing/doctype/bom/bom.py
+++ b/erpnext/manufacturing/doctype/bom/bom.py
@@ -588,7 +588,7 @@
 			for d in self.operations:
 				if not d.description:
 					d.description = frappe.db.get_value('Operation', d.operation, 'description')
-				if not d.batch_size > 0:
+				if not d.batch_size or d.batch_size <= 0:
 					d.batch_size = 1
 
 def get_list_context(context):