diff --git a/src/backend/utils/adt/jsonb.c b/src/backend/utils/adt/jsonb.c
index 8b1cab4..4bd0ee8 100644
--- a/src/backend/utils/adt/jsonb.c
+++ b/src/backend/utils/adt/jsonb.c
@@ -936,7 +936,9 @@ datum_to_jsonb(Datum val, bool is_null, JsonbInState *result,
 				break;
 		}
 	}
-	if (tcategory >= JSONBTYPE_JSON && tcategory <= JSONBTYPE_JSONCAST &&
+	if (tcategory >= JSONBTYPE_JSON &&
+		tcategory <= JSONBTYPE_JSONCAST &&
+		!is_null &&
 		!scalar_jsonb)
 	{
 		/* work has been done recursively */
diff --git a/src/test/regress/expected/jsonb.out b/src/test/regress/expected/jsonb.out
index 07091a9..b99e48c 100644
--- a/src/test/regress/expected/jsonb.out
+++ b/src/test/regress/expected/jsonb.out
@@ -1362,6 +1362,15 @@ SELECT jsonb_build_object(json '{"a":1,"b":2}', 3);
 ERROR:  key value must be scalar, not array, composite or json
 SELECT jsonb_build_object('{1,2,3}'::int[], 3);
 ERROR:  key value must be scalar, not array, composite or json
+-- handling of NULL values
+SELECT jsonb_object_agg(1, NULL::jsonb);
+ jsonb_object_agg 
+------------------
+ {"1": null}
+(1 row)
+
+SELECT jsonb_object_agg(NULL, '{"a":1}');
+ERROR:  field name must not be null
 CREATE TEMP TABLE foo (serial_num int, name text, type text);
 INSERT INTO foo VALUES (847001,'t15','GE1043');
 INSERT INTO foo VALUES (847002,'t16','GE1043');
@@ -1379,9 +1388,6 @@ SELECT jsonb_object_agg(name, type) FROM foo;
  {"t15": "GE1043", "t16": "GE1043", "sub-alpha": "GESS90"}
 (1 row)
 
-INSERT INTO foo VALUES (999999, NULL, 'bar');
-SELECT jsonb_object_agg(name, type) FROM foo;
-ERROR:  field name must not be null
 -- jsonb_object
 -- one dimension
 SELECT jsonb_object('{a,1,b,2,3,NULL,"d e f","a b c"}');
diff --git a/src/test/regress/sql/jsonb.sql b/src/test/regress/sql/jsonb.sql
index 9700b7c..67de991 100644
--- a/src/test/regress/sql/jsonb.sql
+++ b/src/test/regress/sql/jsonb.sql
@@ -330,6 +330,10 @@ SELECT jsonb_build_object(json '{"a":1,"b":2}', 3);
 
 SELECT jsonb_build_object('{1,2,3}'::int[], 3);
 
+-- handling of NULL values
+SELECT jsonb_object_agg(1, NULL::jsonb);
+SELECT jsonb_object_agg(NULL, '{"a":1}');
+
 CREATE TEMP TABLE foo (serial_num int, name text, type text);
 INSERT INTO foo VALUES (847001,'t15','GE1043');
 INSERT INTO foo VALUES (847002,'t16','GE1043');
@@ -340,9 +344,6 @@ FROM foo;
 
 SELECT jsonb_object_agg(name, type) FROM foo;
 
-INSERT INTO foo VALUES (999999, NULL, 'bar');
-SELECT jsonb_object_agg(name, type) FROM foo;
-
 -- jsonb_object
 
 -- one dimension