diff --git a/engineio/packet.py b/engineio/packet.py
index 5e70511a..768bad85 100644
--- a/engineio/packet.py
+++ b/engineio/packet.py
@@ -54,7 +54,7 @@ def encode(self, b64=False, always_bytes=True):
     def decode(self, encoded_packet):
         """Decode a transmitted package."""
         b64 = False
-        if not isinstance(encoded_packet, six.binary_type):
+        if not isinstance(encoded_packet, six.binary_type) and not isinstance(encoded_packet, bytearray):
             encoded_packet = encoded_packet.encode('utf-8')
         self.packet_type = six.byte2int(encoded_packet[0:1])
         if self.packet_type == 98:  # 'b' --> binary base64 encoded packet