diff --git a/requirements-dev.txt b/requirements-dev.txt
index 9ac277d..2a7347d 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -6,6 +6,7 @@ pytest==4.6.9 ; python_version < '3.0'
 pytest==5.3.5 ; python_version >= '3.0'
 pytest-cov==2.8.1
 coveralls==1.11.1
+nose == 1.3.7
 
 # Documentation
 Sphinx==1.8.5 ; python_version < '3.5'
diff --git a/skosprovider_getty/utils.py b/skosprovider_getty/utils.py
index c609cc2..5d39d3f 100644
--- a/skosprovider_getty/utils.py
+++ b/skosprovider_getty/utils.py
@@ -279,7 +279,10 @@ def hierarchy_notetypes(list):
 
 
 def uri_to_id(uri):
-    return uri.strip('/').rsplit('/', 1)[1]
+    try:
+        return uri.strip('/').rsplit('/', 1)[1]
+    except IndexError:
+        return uri
 
 
 def uri_to_graph(uri, **kwargs):
diff --git a/tests/test_providers.py b/tests/test_providers.py
index d14fb92..1cfab26 100644
--- a/tests/test_providers.py
+++ b/tests/test_providers.py
@@ -123,6 +123,11 @@ def test_get_by_uri(self):
         self.assertEqual(concept['uri'], 'http://vocab.getty.edu/aat/300007466')
         self.assertEqual(concept['id'], '300007466')
 
+    def test_get_by_uri_invalid(self):
+        # Default GettyProvider is an AAT provider
+        concept = GettyProvider({'id': 'AAT'}).get_by_uri('urn:skosprovider:5')
+        self.assertFalse(concept)
+
     def test_get_by_id_tgn(self):
         concept = TGNProvider({'id': 'TGN'}).get_by_id('1000063')
         concept = concept.__dict__