diff --git a/erpnext/accounts/doctype/purchase_invoice/purchase_invoice.js b/erpnext/accounts/doctype/purchase_invoice/purchase_invoice.js
index b4fd91f..c94c85c 100644
--- a/erpnext/accounts/doctype/purchase_invoice/purchase_invoice.js
+++ b/erpnext/accounts/doctype/purchase_invoice/purchase_invoice.js
@@ -510,6 +510,15 @@
 				}
 			}
 		}
+
+		frm.set_query("cost_center", function() {
+			return {
+				filters: {
+					company: frm.doc.company,
+					is_group: 0
+				}
+			};
+		});
 	},
 
 	onload: function(frm) {
diff --git a/erpnext/accounts/doctype/sales_invoice/sales_invoice.js b/erpnext/accounts/doctype/sales_invoice/sales_invoice.js
index 3816632..0399cf9 100644
--- a/erpnext/accounts/doctype/sales_invoice/sales_invoice.js
+++ b/erpnext/accounts/doctype/sales_invoice/sales_invoice.js
@@ -564,6 +564,15 @@
 			};
 		});
 
+		frm.set_query("cost_center", function() {
+			return {
+				filters: {
+					company: frm.doc.company,
+					is_group: 0
+				}
+			};
+		});
+
 		frm.custom_make_buttons = {
 			'Delivery Note': 'Delivery',
 			'Sales Invoice': 'Sales Return',
diff --git a/erpnext/buying/doctype/purchase_order/purchase_order.py b/erpnext/buying/doctype/purchase_order/purchase_order.py
index a4a636d..7201606 100644
--- a/erpnext/buying/doctype/purchase_order/purchase_order.py
+++ b/erpnext/buying/doctype/purchase_order/purchase_order.py
@@ -388,9 +388,10 @@
 
 		item = get_item_defaults(target.item_code, source_parent.company)
 		item_group = get_item_group_defaults(target.item_code, source_parent.company)
-		target.cost_center = frappe.db.get_value("Project", obj.project, "cost_center") \
-			or item.get("buying_cost_center") \
-			or item_group.get("buying_cost_center")
+		target.cost_center = (obj.cost_center
+			or frappe.db.get_value("Project", obj.project, "cost_center")
+			or item.get("buying_cost_center")
+			or item_group.get("buying_cost_center"))
 
 	doc = get_mapped_doc("Purchase Order", source_name,	{
 		"Purchase Order": {