diff --git a/quickbooks/objects/invoice.py b/quickbooks/objects/invoice.py
index 7db64818..ddcdb943 100644
--- a/quickbooks/objects/invoice.py
+++ b/quickbooks/objects/invoice.py
@@ -104,3 +104,12 @@ def email_sent(self):
             return True
 
         return False
+
+    def to_ref(self):
+        ref = Ref()
+
+        ref.name = self.DocNumber
+        ref.type = self.qbo_object_name
+        ref.value = self.Id
+
+        return ref
diff --git a/tests/unit/objects/test_invoice.py b/tests/unit/objects/test_invoice.py
index 9a45a628..53d2d669 100644
--- a/tests/unit/objects/test_invoice.py
+++ b/tests/unit/objects/test_invoice.py
@@ -39,6 +39,17 @@ def test_valid_object_name(self):
 
         self.assertTrue(result)
 
+    def test_to_ref(self):
+        invoice = Invoice()
+        invoice.DocNumber = 1
+        invoice.Id = 2
+
+        ref = invoice.to_ref()
+        self.assertIsInstance(ref, Ref)
+        self.assertEquals(ref.type, "Invoice")
+        self.assertEquals(ref.name, 1)  # should be DocNumber
+        self.assertEquals(ref.value, 2)  # should be Id
+
 
 class DeliveryInfoTests(unittest.TestCase):
     def test_init(self):