diff --git a/erpnext/patches/v10_0/update_reserved_qty_for_purchase_order.py b/erpnext/patches/v10_0/update_reserved_qty_for_purchase_order.py
new file mode 100644
index 0000000..f0de423
--- /dev/null
+++ b/erpnext/patches/v10_0/update_reserved_qty_for_purchase_order.py
@@ -0,0 +1,48 @@
+import frappe
+from frappe import _
+from erpnext.stock.utils import get_bin
+
+def execute():
+	po_item = list(frappe.db.sql(("""
+		select distinct po.name as poname, poitem.rm_item_code as rm_item_code, po.company
+		from `tabPurchase Order` po, `tabPurchase Order Item Supplied` poitem
+		where po.name = poitem.parent
+			and po.is_subcontracted = "Yes"
+			and po.docstatus = 1"""), as_dict=1))
+	if not po_item:
+		return
+
+	company_warehouse = frappe._dict(frappe.db.sql("""select company, min(name) from `tabWarehouse`
+		where is_group = 0 group by company"""))
+
+	items = list(set([d.rm_item_code for d in po_item]))
+	item_wh = frappe._dict(frappe.db.sql("""select item_code, default_warehouse
+		from `tabItem` where name in ({0})""".format(", ".join(["%s"] * len(items))), items))
+
+	# Update reserved warehouse
+	for item in po_item:
+		reserve_warehouse = get_warehouse(item.rm_item_code, item.company, company_warehouse, item_wh)
+		update_res_warehouse = frappe.db.sql("""update `tabPurchase Order Item Supplied`
+			set reserve_warehouse = %s
+			where parent = %s and rm_item_code = %s
+		""", (reserve_warehouse, item["poname"], item["rm_item_code"]))
+
+	# Update bin
+	item_wh_bin = frappe.db.sql(("""
+		select distinct poitemsup.rm_item_code as rm_item_code, 
+			poitemsup.reserve_warehouse as reserve_warehouse
+		from `tabPurchase Order` po, `tabPurchase Order Item Supplied` poitemsup
+		where po.name = poitemsup.parent
+			and po.is_subcontracted = "Yes"
+			and po.docstatus = 1"""), as_dict=1)
+	for d in item_wh_bin:
+		stock_bin = get_bin(d["rm_item_code"], d["reserve_warehouse"])
+		stock_bin.update_reserved_qty_for_sub_contracting()
+
+def get_warehouse(item_code, company, company_warehouse, item_wh):
+	reserve_warehouse = item_wh.get(item_code)
+	if frappe.db.get_value("Warehouse", reserve_warehouse, "company") != company:
+		reserve_warehouse = None
+	if not reserve_warehouse:
+		reserve_warehouse = company_warehouse.get(company)
+	return reserve_warehouse
\ No newline at end of file