diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2f17896..c120638 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@ Version 1.7 (in development)
 ----------------------------
 
 - Added support pickling/unpickling resources.
+- Added support for `datetime` objects in API requests.
 
 
 Version 1.6
diff --git a/pillarsdk/utils.py b/pillarsdk/utils.py
index 7ca5f3a..c2838bb 100644
--- a/pillarsdk/utils.py
+++ b/pillarsdk/utils.py
@@ -77,7 +77,7 @@ def join_url_params(url, params):
 
     def convert_to_string(param):
         if isinstance(param, dict):
-            return json.dumps(param, sort_keys=True)
+            return json.dumps(param, sort_keys=True, cls=PillarJSONEncoder)
         if isinstance(param, text_type):
             return param.encode('utf-8')
         return param