diff --git a/app/core/admin.py b/app/core/admin.py
index dd431c5..c10ade5 100644
--- a/app/core/admin.py
+++ b/app/core/admin.py
@@ -108,5 +108,5 @@ def get_form(self, request, obj=None, **kwargs):
         form = super(TermAdmin, self).get_form(request, obj, **kwargs)
         if obj is not None:
             form.base_fields['mapping'].queryset = Term.objects.exclude(
-                iri__startswith=obj.root_term_set())
+                iri__istartswith=obj.root_term_set())
         return form
diff --git a/app/core/models.py b/app/core/models.py
index 28bede0..315f256 100644
--- a/app/core/models.py
+++ b/app/core/models.py
@@ -233,7 +233,7 @@ def path(self):
 
     def mapped_to(self, target_root):
         """Return path if Term is mapped to anything in target_root string"""
-        target_map = self.mapping.filter(iri__startswith=target_root)
+        target_map = self.mapping.filter(iri__istartswith=target_root)
         if target_map.exists():
             return target_map.first().path()
         return None