diff --git a/matrix/buffer.py b/matrix/buffer.py
index 8501ed5..ca62bfe 100644
--- a/matrix/buffer.py
+++ b/matrix/buffer.py
@@ -1375,7 +1375,7 @@ class RoomBuffer(object):
         else:
             data = Render.encrypted_media(
                 event.url, event.body, event.key["k"], event.hashes["sha256"],
-                event.iv, self.homeserver.geturl()
+                event.iv, self.homeserver.geturl(), event.mimetype,
             )
 
         extra_prefix = (self.warning_prefix if event.decrypted
diff --git a/matrix/message_renderer.py b/matrix/message_renderer.py
index baa1fda..8a6f544 100644
--- a/matrix/message_renderer.py
+++ b/matrix/message_renderer.py
@@ -42,14 +42,15 @@ class Render(object):
         return Render._media(url, description)
 
     @staticmethod
-    def encrypted_media(mxc, body, key, hash,  iv, homeserver=None):
+    def encrypted_media(mxc, body, key, hash, iv, homeserver=None, mime=None):
         """Render a mxc media URI of an encrypted file."""
         http_url = Api.encrypted_mxc_to_plumb(
             mxc,
             key,
             hash,
             iv,
-            homeserver
+            homeserver,
+            mime,
         )
         url = http_url if http_url else mxc
         description = "{}".format(body) if body else "file"
diff --git a/matrix/uploads.py b/matrix/uploads.py
index 0b4e1f8..5757c60 100644
--- a/matrix/uploads.py
+++ b/matrix/uploads.py
@@ -214,6 +214,7 @@ class Upload(object):
                 self.file_keys["key"]["k"],
                 self.file_keys["hashes"]["sha256"],
                 self.file_keys["iv"],
+                mimetype=self.file_keys.get("mimetype"),
             )
 
         return Render.media(self.content_uri, self.file_name)