diff --git a/Include/mappingobject.h b/Include/mappingobject.h
index f6d36e0d1bd..7d006dd568a 100644
--- a/Include/mappingobject.h
+++ b/Include/mappingobject.h
@@ -44,6 +44,7 @@ extern int mappinggetnext
 extern object *getmappingkeys PROTO((object *mp));
 extern object *getmappingvalues PROTO((object *mp));
 extern object *getmappingitems PROTO((object *mp));
+extern int getmappingsize PROTO((object *mp));
 
 #ifdef __cplusplus
 }
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 2a51d51dae2..b89b7b2786a 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -566,6 +566,17 @@ mapping_items(mp, args)
 	return v;
 }
 
+int
+getmappingsize(mp)
+	object *mp;
+{
+	if (mp == NULL || !is_mappingobject(mp)) {
+		err_badcall();
+		return NULL;
+	}
+	return ((mappingobject *)mp)->ma_used;
+}
+
 object *
 getmappingkeys(mp)
 	object *mp;
diff --git a/Objects/mappingobject.c b/Objects/mappingobject.c
index 2a51d51dae2..b89b7b2786a 100644
--- a/Objects/mappingobject.c
+++ b/Objects/mappingobject.c
@@ -566,6 +566,17 @@ mapping_items(mp, args)
 	return v;
 }
 
+int
+getmappingsize(mp)
+	object *mp;
+{
+	if (mp == NULL || !is_mappingobject(mp)) {
+		err_badcall();
+		return NULL;
+	}
+	return ((mappingobject *)mp)->ma_used;
+}
+
 object *
 getmappingkeys(mp)
 	object *mp;