diff --git a/gen/gen.go b/gen/gen.go
index 105b89c6f..39ed0489b 100644
--- a/gen/gen.go
+++ b/gen/gen.go
@@ -176,7 +176,11 @@ func (g *Gen) Build(config *Config) error {
 }
 
 func (g *Gen) writeDocSwagger(config *Config, swagger *spec.Swagger) error {
-	docFileName := path.Join(config.OutputDir, "docs.go")
+	var filename = "docs.go"
+	if config.InstanceName != swag.Name {
+		filename = config.InstanceName + "_" + filename
+	}
+	docFileName := path.Join(config.OutputDir, filename)
 
 	absOutputDir, err := filepath.Abs(config.OutputDir)
 	if err != nil {
@@ -201,7 +205,11 @@ func (g *Gen) writeDocSwagger(config *Config, swagger *spec.Swagger) error {
 }
 
 func (g *Gen) writeJSONSwagger(config *Config, swagger *spec.Swagger) error {
-	jsonFileName := path.Join(config.OutputDir, "swagger.json")
+	var filename = "swagger.json"
+	if config.InstanceName != swag.Name {
+		filename = config.InstanceName + "_" + filename
+	}
+	jsonFileName := path.Join(config.OutputDir, filename)
 
 	b, err := g.jsonIndent(swagger)
 	if err != nil {
@@ -218,7 +226,11 @@ func (g *Gen) writeJSONSwagger(config *Config, swagger *spec.Swagger) error {
 }
 
 func (g *Gen) writeYAMLSwagger(config *Config, swagger *spec.Swagger) error {
-	yamlFileName := path.Join(config.OutputDir, "swagger.yaml")
+	var filename = "swagger.yaml"
+	if config.InstanceName != swag.Name {
+		filename = config.InstanceName + "_" + filename
+	}
+	yamlFileName := path.Join(config.OutputDir, filename)
 
 	b, err := g.json(swagger)
 	if err != nil {
diff --git a/gen/gen_test.go b/gen/gen_test.go
index c44b32b8f..0447ec9f5 100644
--- a/gen/gen_test.go
+++ b/gen/gen_test.go
@@ -101,6 +101,7 @@ func TestGen_BuildInstanceName(t *testing.T) {
 
 	// Custom name
 	config.InstanceName = "custom"
+	goSourceFile = filepath.Join(config.OutputDir, config.InstanceName+"_"+"docs.go")
 	assert.NoError(t, New().Build(config))
 	expectedCode, err = ioutil.ReadFile(goSourceFile)
 	if err != nil {
@@ -112,9 +113,9 @@ func TestGen_BuildInstanceName(t *testing.T) {
 
 	// cleanup
 	expectedFiles := []string{
-		filepath.Join(config.OutputDir, "docs.go"),
-		filepath.Join(config.OutputDir, "swagger.json"),
-		filepath.Join(config.OutputDir, "swagger.yaml"),
+		filepath.Join(config.OutputDir, config.InstanceName+"_"+"docs.go"),
+		filepath.Join(config.OutputDir, config.InstanceName+"_"+"swagger.json"),
+		filepath.Join(config.OutputDir, config.InstanceName+"_"+"swagger.yaml"),
 	}
 	for _, expectedFile := range expectedFiles {
 		if _, err := os.Stat(expectedFile); os.IsNotExist(err) {