diff --git a/erpnext/patches.txt b/erpnext/patches.txt
index 9eaa012..85bf3cb 100644
--- a/erpnext/patches.txt
+++ b/erpnext/patches.txt
@@ -215,3 +215,4 @@
 erpnext.patches.v6_4.repost_gle_for_journal_entries_where_reference_name_missing
 erpnext.patches.v6_4.fix_journal_entries_due_to_reconciliation
 erpnext.patches.v6_4.fix_status_in_sales_and_purchase_order
+erpnext.patches.v6_4.fix_modified_in_sales_order_and_purchase_order
\ No newline at end of file
diff --git a/erpnext/patches/v6_4/fix_modified_in_sales_order_and_purchase_order.py b/erpnext/patches/v6_4/fix_modified_in_sales_order_and_purchase_order.py
new file mode 100644
index 0000000..f27489e
--- /dev/null
+++ b/erpnext/patches/v6_4/fix_modified_in_sales_order_and_purchase_order.py
@@ -0,0 +1,10 @@
+from __future__ import unicode_literals
+import frappe
+
+def execute():
+	for doctype in ("Sales Order", "Purchase Order"):
+		data = frappe.db.sql("""select parent, modified_by, modified
+			from `tab{doctype} Item` where docstatus=1 group by parent""".format(doctype=doctype), as_dict=True)
+		for item in data:
+			frappe.db.sql("""update `tab{doctype}` set modified_by=%(modified_by)s, modified=%(modified)s
+				where name=%(parent)s""".format(doctype=doctype), item)