Index: django/db/models/manipulators.py
===================================================================
--- django/db/models/manipulators.py	(Revision 5468)
+++ django/db/models/manipulators.py	(Arbeitskopie)
@@ -281,9 +281,9 @@
     from django.utils.text import get_text_list
     field_list = [opts.get_field(field_name) for field_name in field_name_list]
     if isinstance(field_list[0].rel, ManyToOneRel):
-        kwargs = {'%s__%s__iexact' % (field_name_list[0], field_list[0].rel.field_name): field_data}
+        kwargs = {'%s__%s__exact' % (field_name_list[0], field_list[0].rel.field_name): field_data}
     else:
-        kwargs = {'%s__iexact' % field_name_list[0]: field_data}
+        kwargs = {'%s__exact' % field_name_list[0]: field_data}
     for f in field_list[1:]:
         # This is really not going to work for fields that have different
         # form fields, e.g. DateTime.
@@ -296,7 +296,7 @@
         if isinstance(f.rel, ManyToOneRel):
             kwargs['%s__pk' % f.name] = field_val
         else:
-            kwargs['%s__iexact' % f.name] = field_val
+            kwargs['%s__exact' % f.name] = field_val
     try:
         old_obj = self.manager.get(**kwargs)
     except ObjectDoesNotExist: