diff --git a/tests/data/enum_options_with_search/sponsors.xls b/tests/data/enum_options_with_search/sponsors.xls
new file mode 100644
index 00000000..7c6b1730
Binary files /dev/null and b/tests/data/enum_options_with_search/sponsors.xls differ
diff --git a/tests/test_lookup_service.py b/tests/test_lookup_service.py
index dda8772c..15157e46 100644
--- a/tests/test_lookup_service.py
+++ b/tests/test_lookup_service.py
@@ -176,3 +176,21 @@ class TestLookupService(BaseTest):
         first_result = result[0]
         self.assertEquals(1000, first_result['CUSTOMER_NUMBER'])
         self.assertEquals('UVA - INTERNAL - GM USE ONLY', first_result['CUSTOMER_NAME'])
+
+    def test_lookup_fails_for_xls(self):
+        BaseTest.load_test_spec('enum_options_with_search')
+
+        # Using an old xls file should raise an error
+        file_model_xls = session.query(FileModel).filter(FileModel.name == 'sponsors.xls').first()
+        file_data_model_xls = session.query(FileDataModel).filter(FileDataModel.file_model_id == file_model_xls.id).first()
+        with self.assertRaises(ApiError) as ae:
+            LookupService.build_lookup_table(file_data_model_xls, 'CUSTOMER_NUMBER', 'CUSTOMER_NAME')
+        self.assertIn('Error opening excel file', ae.exception.args[0])
+
+        # Using an xlsx file should work
+        file_model_xlsx = session.query(FileModel).filter(FileModel.name == 'sponsors.xlsx').first()
+        file_data_model_xlsx = session.query(FileDataModel).filter(FileDataModel.file_model_id == file_model_xlsx.id).first()
+        lookup_model = LookupService.build_lookup_table(file_data_model_xlsx, 'CUSTOMER_NUMBER', 'CUSTOMER_NAME')
+        self.assertEqual(28, len(lookup_model.dependencies))
+        self.assertIn('CUSTOMER_NAME', lookup_model.dependencies[0].data.keys())
+        self.assertIn('CUSTOMER_NUMBER', lookup_model.dependencies[0].data.keys())