diff --git a/session_redis/json_encoding.py b/session_redis/json_encoding.py
new file mode 100644
index 0000000..f535a8f
--- /dev/null
+++ b/session_redis/json_encoding.py
@@ -0,0 +1,43 @@
+# Copyright 2016-2020 Camptocamp SA
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html)
+
+import json
+
+from datetime import date, datetime
+
+import dateutil
+
+
+class SessionEncoder(json.JSONEncoder):
+    """Encode date/datetime objects
+
+    So that we can later recompose them if they were stored in the session
+    """
+
+    def default(self, obj):
+        if isinstance(obj, datetime):
+            return {"_type": "datetime_isoformat", "value": obj.isoformat()}
+        elif isinstance(obj, date):
+            return {"_type": "date_isoformat", "value": obj.isoformat()}
+        elif isinstance(obj, set):
+            return {"_type": "set", "value": tuple(obj)}
+        return json.JSONEncoder.default(self, obj)
+
+
+class SessionDecoder(json.JSONDecoder):
+    """Decode json, recomposing recordsets and date/datetime"""
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(object_hook=self.object_hook, *args, **kwargs)
+
+    def object_hook(self, obj):
+        if "_type" not in obj:
+            return obj
+        type_ = obj["_type"]
+        if type_ == "datetime_isoformat":
+            return dateutil.parser.parse(obj["value"])
+        elif type_ == "date_isoformat":
+            return dateutil.parser.parse(obj["value"]).date()
+        elif type_ == "set":
+            return set(obj["value"])
+        return obj
diff --git a/session_redis/session.py b/session_redis/session.py
index 8b9e5af..0d73b0a 100644
--- a/session_redis/session.py
+++ b/session_redis/session.py
@@ -6,6 +6,8 @@ import logging
 
 from werkzeug.contrib.sessions import SessionStore
 
+from . import json_encoding
+
 # this is equal to the duration of the session garbage collector in
 # odoo.http.session_gc()
 DEFAULT_SESSION_TIMEOUT = 60 * 60 * 24 * 7  # 7 days in seconds
@@ -57,7 +59,9 @@ class RedisSessionStore(SessionStore):
                           "expiration of %s seconds for %s",
                           key, expiration, user_msg)
 
-        data = json.dumps(dict(session)).encode('utf-8')
+        data = json.dumps(
+            dict(session), cls=json_encoding.SessionEncoder
+        ).encode('utf-8')
         if self.redis.set(key, data):
             return self.redis.expire(key, expiration)
 
@@ -79,7 +83,9 @@ class RedisSessionStore(SessionStore):
                           "returning a new one", key)
             return self.new()
         try:
-            data = json.loads(saved.decode('utf-8'))
+            data = json.loads(
+                saved.decode('utf-8'), cls=json_encoding.SessionDecoder
+            )
         except ValueError:
             _logger.debug("session for key '%s' has been asked but its json "
                           "content could not be read, it has been reset", key)