diff --git a/client/src/containers/Expenses/ExpenseForm.schema.js b/client/src/containers/Expenses/ExpenseForm.schema.js
index 8a5a6fd74..adb5ee608 100644
--- a/client/src/containers/Expenses/ExpenseForm.schema.js
+++ b/client/src/containers/Expenses/ExpenseForm.schema.js
@@ -11,7 +11,7 @@ const Schema = Yup.object().shape({
   payment_date: Yup.date()
     .required()
     .label(formatMessage({ id: 'payment_date_' })),
-  reference_no: Yup.string().min(1).max(DATATYPES_LENGTH.STRING),
+  reference_no: Yup.string().min(1).max(DATATYPES_LENGTH.STRING).nullable(),
   currency_code: Yup.string()
     .nullable()
     .max(3)