diff --git a/policy.go b/policy.go
index 15e62c1..61fb15c 100644
--- a/policy.go
+++ b/policy.go
@@ -68,7 +68,7 @@ func (p *policy) loadConfig(config Config) {
 			stsSub = "; includeSubdomains"
 		}
 		if config.STSPreload {
-			stsSub = "; preload"
+			stsSub += "; preload"
 		}
 		// TODO
 		// "max-age=%d%s" refactor
diff --git a/secure_test.go b/secure_test.go
index f581a1d..7665d3b 100644
--- a/secure_test.go
+++ b/secure_test.go
@@ -285,6 +285,19 @@ func TestStsHeaderWithSubdomain(t *testing.T) {
 	assert.Equal(t, "max-age=315360000; includeSubdomains", w.Header().Get("Strict-Transport-Security"))
 }
 
+func TestStsHeaderWithSubdomainAndPreload(t *testing.T) {
+	router := newServer(Config{
+		STSSeconds:           315360000,
+		STSIncludeSubdomains: true,
+		STSPreload:           true,
+	})
+
+	w := performRequest(router, "/foo")
+
+	assert.Equal(t, http.StatusOK, w.Code)
+	assert.Equal(t, "max-age=315360000; includeSubdomains; preload", w.Header().Get("Strict-Transport-Security"))
+}
+
 func TestFrameDeny(t *testing.T) {
 	router := newServer(Config{
 		FrameDeny: true,