diff --git a/websocket-sharp/Net/Cookie.cs b/websocket-sharp/Net/Cookie.cs
index 5fd622fe..785300c3 100644
--- a/websocket-sharp/Net/Cookie.cs
+++ b/websocket-sharp/Net/Cookie.cs
@@ -96,6 +96,7 @@ namespace WebSocketSharp.Net
     private string                 _port;
     private int[]                  _ports;
     private static readonly char[] _reservedCharsForValue;
+    private string                 _sameSite;
     private bool                   _secure;
     private DateTime               _timeStamp;
     private string                 _value;
@@ -350,6 +351,16 @@ namespace WebSocketSharp.Net
       }
     }
 
+    internal string SameSite {
+      get {
+        return _sameSite;
+      }
+
+      set {
+        _sameSite = value;
+      }
+    }
+
     #endregion
 
     #region Public Properties
@@ -768,6 +779,9 @@ namespace WebSocketSharp.Net
       if (!_domain.IsNullOrEmpty ())
         buff.AppendFormat ("; Domain={0}", _domain);
 
+      if (!_sameSite.IsNullOrEmpty ())
+        buff.AppendFormat ("; SameSite={0}", _sameSite);
+
       if (_secure)
         buff.Append ("; Secure");
 
diff --git a/websocket-sharp/Net/CookieCollection.cs b/websocket-sharp/Net/CookieCollection.cs
index e5939642..8c0322bd 100644
--- a/websocket-sharp/Net/CookieCollection.cs
+++ b/websocket-sharp/Net/CookieCollection.cs
@@ -526,6 +526,17 @@ namespace WebSocketSharp.Net
           continue;
         }
 
+        if (name.Equals ("samesite", caseInsensitive)) {
+          if (cookie == null)
+            continue;
+
+          if (val.Length == 0)
+            continue;
+
+          cookie.SameSite = val.Unquote ();
+          continue;
+        }
+
         if (cookie != null)
           ret.add (cookie);