diff --git a/Tests/UuidTest.php b/Tests/UuidTest.php
index 5e05b89..cb7ac10 100644
--- a/Tests/UuidTest.php
+++ b/Tests/UuidTest.php
@@ -95,6 +95,15 @@ public function testV1()
         $this->assertSame('3499710062d0', $uuid->getNode());
     }
 
+    public function testV1IsLowerCase()
+    {
+        $uuid = new UuidV1();
+        $this->assertSame(strtolower((string) $uuid), (string) $uuid);
+
+        $uuid = new UuidV1('D9E7A184-5D5B-11EA-A62A-3499710062D0');
+        $this->assertSame(strtolower((string) $uuid), (string) $uuid);
+    }
+
     public function testV3()
     {
         $uuid = Uuid::v3(new UuidV4(self::A_UUID_V4), 'the name');
diff --git a/UuidV1.php b/UuidV1.php
index 1ec0041..1e68737 100644
--- a/UuidV1.php
+++ b/UuidV1.php
@@ -25,7 +25,7 @@ class UuidV1 extends Uuid implements TimeBasedUidInterface
     public function __construct(?string $uuid = null)
     {
         if (null === $uuid) {
-            $this->uid = uuid_create(static::TYPE);
+            $this->uid = strtolower(uuid_create(static::TYPE));
         } else {
             parent::__construct($uuid, true);
         }