diff --git a/oscar_elasticsearch/search/mappings/products/mappings.py b/oscar_elasticsearch/search/mappings/products/mappings.py
index 049fb10..37fe345 100644
--- a/oscar_elasticsearch/search/mappings/products/mappings.py
+++ b/oscar_elasticsearch/search/mappings/products/mappings.py
@@ -164,3 +164,8 @@ def suggest(self, *args):
     )
     def title(self, title):
         return title, title, title
+
+    @odin.assign_field
+    def parent_id(self):
+        if self.source.parent:
+            return self.source.parent.id