diff --git a/src/RequestMethodInterface.php b/src/RequestMethodInterface.php
new file mode 100644
index 0000000..1d06299
--- /dev/null
+++ b/src/RequestMethodInterface.php
@@ -0,0 +1,18 @@
+<?php
+namespace Psr\Http\Message;
+
+/**
+ * The interface defines constants request method
+ */
+interface RequestMethodInterface {
+    const METHOD_HEAD = 'HEAD';
+    const METHOD_GET = 'GET';
+    const METHOD_POST = 'POST';
+    const METHOD_PUT = 'PUT';
+    const METHOD_PATCH = 'PATCH';
+    const METHOD_DELETE = 'DELETE';
+    const METHOD_PURGE = 'PURGE';
+    const METHOD_OPTIONS = 'OPTIONS';
+    const METHOD_TRACE = 'TRACE';
+    const METHOD_CONNECT = 'CONNECT';
+}