diff --git a/djaa_list_filter/admin.py b/djaa_list_filter/admin.py
index 66d2d9d..4201ebe 100644
--- a/djaa_list_filter/admin.py
+++ b/djaa_list_filter/admin.py
@@ -46,7 +46,7 @@ class AjaxAutocompleteSelectWidget(AutocompleteSelect):
 
 class AjaxAutocompleteListFilter(admin.RelatedFieldListFilter):
     title = _('list filter')
-    parameter_name = '%s__%s__exact'
+    parameter_name = '%s_%s__exact'
     template = 'djaa_list_filter/admin/filter/autocomplete_list_filter.html'
 
     def __init__(self, field, request, params, model, model_admin, field_path):