diff --git a/coapthon/messages/message.py b/coapthon/messages/message.py
index 6364bf8..d8159f9 100644
--- a/coapthon/messages/message.py
+++ b/coapthon/messages/message.py
@@ -119,17 +119,16 @@ class Message(object):
         """
         Set the Token of the message.
 
-        :type value: String
+        :type value: Bytes
         :param value: the Token
         :raise AttributeError: if value is longer than 256
         """
         if value is None:
             self._token = value
             return
-        if isinstance(value, int):
-            value = bytes([value])
         if not isinstance(value, bytes):
-            value = bytes(value, "utf-8")
+            value = bytes(value)
+
         if len(value) > 256:
             raise AttributeError
         self._token = value
diff --git a/coapthon/serializer.py b/coapthon/serializer.py
index 3b5e914..2f4683f 100644
--- a/coapthon/serializer.py
+++ b/coapthon/serializer.py
@@ -157,10 +157,8 @@ class Serializer(object):
         values = [tmp, message.code, message.mid]
 
         if message.token is not None and tkl > 0:
-
-            for b in message.token:
-                fmt += "B"
-                values.append(b)
+            fmt += "%ss" % tkl
+            values.append(message.token)
 
         options = Serializer.as_sorted_list(message.options)  # already sorted
         lastoptionnumber = 0