diff --git a/pymisp/abstract.py b/pymisp/abstract.py
index 0e2d486..6b13143 100644
--- a/pymisp/abstract.py
+++ b/pymisp/abstract.py
@@ -6,6 +6,7 @@ import datetime
 
 from deprecated import deprecated
 from json import JSONEncoder
+from uuid import UUID
 
 try:
     from rapidjson import load
@@ -123,6 +124,8 @@ class MISPEncode(JSONEncoder):
             return obj.isoformat()
         elif isinstance(obj, Enum):
             return obj.value
+        elif isinstance(obj, UUID):
+            return str(obj)
         return JSONEncoder.default(self, obj)
 
 
@@ -134,6 +137,8 @@ if HAS_RAPIDJSON:
             return obj.isoformat()
         elif isinstance(obj, Enum):
             return obj.value
+        elif isinstance(obj, UUID):
+            return str(obj)
         return rapidjson.default(obj)
 else:
     def pymisp_json_default(obj):
@@ -143,6 +148,8 @@ else:
             return obj.isoformat()
         elif isinstance(obj, Enum):
             return obj.value
+        elif isinstance(obj, UUID):
+            return str(obj)
         return json.default(obj)
 
 
diff --git a/pymisp/mispevent.py b/pymisp/mispevent.py
index e3a10e8..47e4cf5 100644
--- a/pymisp/mispevent.py
+++ b/pymisp/mispevent.py
@@ -220,7 +220,14 @@ class MISPAttribute(AbstractMISP):
         if self.value is None:
             raise NewAttributeError('The value of the attribute is required.')
         if self.type == 'datetime' and isinstance(self.value, str):
-            self.value = parse(self.value)
+            try:
+                if '.' in self.value:
+                    self.value = datetime.datetime.strptime(self.value, "%Y-%m-%dT%H:%M:%S.%f")
+                else:
+                    self.value = datetime.datetime.strptime(self.value, "%Y-%m-%dT%H:%M:%S")
+            except ValueError:
+                # Slower, but if the other ones fail, that's a good fallback
+                self.value = parse(self.value)
 
         # Default values
         self.category = kwargs.pop('category', type_defaults['default_category'])