diff --git a/requirements.txt b/requirements.txt
index f9cb448..879c361 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,3 +4,4 @@ boto >=2.0b4
 bunch >=1.0.0
 # 0.14 switches to libev, that means bootstrap needs to change too
 gevent ==0.13.6
+isodate >=0.4.4
diff --git a/setup.py b/setup.py
index 57d1b61..1fc636c 100644
--- a/setup.py
+++ b/setup.py
@@ -17,6 +17,7 @@ setup(
         'PyYAML',
         'bunch >=1.0.0',
         'gevent ==0.13.6',
+        'isodate >=0.4.4',
         ],
 
     entry_points={