diff --git a/apps/inm/filters.py b/apps/inm/filters.py
index 9b729afc..ac89822e 100644
--- a/apps/inm/filters.py
+++ b/apps/inm/filters.py
@@ -1,5 +1,6 @@
 from django_filters import rest_framework as filters
 from apps.inm.models import MaterialBatch, MIO
+from django.db.models import Q
 
 
 class MaterialBatchFilter(filters.FilterSet):
@@ -32,10 +33,10 @@ class MioFilter(filters.FilterSet):
 
     def filter_materials__type(self, queryset, name, value):
         if value:
-            return queryset.filter(materials__type=value).distinct()
+            return queryset.filter(Q(materials__type=value) | Q(materials__isnull=True)).distinct()
         return queryset
 
     def filter_materials__type__in(self, queryset, name, value):
         if value:
-            return queryset.filter(materials__type__in=value.split(',')).distinct()
+            return queryset.filter(Q(materials__type__in=value.split(',')) | Q(materials__isnull=True)).distinct()
         return queryset