diff --git a/json_test.go b/json_test.go
index b5eae09..2866b8d 100644
--- a/json_test.go
+++ b/json_test.go
@@ -30,3 +30,32 @@
 		t.Errorf("got %#v, want %#v", s2, s1)
 	}
 }
+
+func BenchmarkUUID_MarshalJSON(b *testing.B) {
+	x := &struct {
+		UUID UUID `json:"uuid"`
+	}{}
+	x.UUID = Parse("f47ac10b-58cc-0372-8567-0e02b2c3d479")
+	if x.UUID == nil {
+		b.Fatal("invalid uuid")
+	}
+	for i := 0; i < b.N; i++ {
+		js, err := json.Marshal(x)
+		if err != nil {
+			b.Fatalf("marshal json: %#v (%v)", js, err)
+		}
+	}
+}
+
+func BenchmarkUUID_UnmarshalJSON(b *testing.B) {
+	js := []byte(`{"uuid":"f47ac10b-58cc-0372-8567-0e02b2c3d479"}`)
+	var x *struct {
+		UUID UUID `json:"uuid"`
+	}
+	for i := 0; i < b.N; i++ {
+		err := json.Unmarshal(js, &x)
+		if err != nil {
+			b.Fatalf("marshal json: %#v (%v)", js, err)
+		}
+	}
+}
diff --git a/uuid_test.go b/uuid_test.go
old mode 100755
new mode 100644
index 417ebeb..3bef767
--- a/uuid_test.go
+++ b/uuid_test.go
@@ -388,3 +388,42 @@
 		t.Errorf("unexecpted duplicates, got %q\n", uuid1)
 	}
 }
+
+func BenchmarkParse(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		uuid := Parse("f47ac10b-58cc-0372-8567-0e02b2c3d479")
+		if uuid == nil {
+			b.Fatal("invalid uuid")
+		}
+	}
+}
+
+func BenchmarkNew(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		New()
+	}
+}
+
+func BenchmarkUUID_String(b *testing.B) {
+	uuid := Parse("f47ac10b-58cc-0372-8567-0e02b2c3d479")
+	if uuid == nil {
+		b.Fatal("invalid uuid")
+	}
+	for i := 0; i < b.N; i++ {
+		if uuid.String() == "" {
+			b.Fatal("invalid uuid")
+		}
+	}
+}
+
+func BenchmarkUUID_URN(b *testing.B) {
+	uuid := Parse("f47ac10b-58cc-0372-8567-0e02b2c3d479")
+	if uuid == nil {
+		b.Fatal("invalid uuid")
+	}
+	for i := 0; i < b.N; i++ {
+		if uuid.URN() == "" {
+			b.Fatal("invalid uuid")
+		}
+	}
+}