diff --git a/odata/property.py b/odata/property.py
index 35814ed..2c7fc02 100644
--- a/odata/property.py
+++ b/odata/property.py
@@ -194,6 +194,16 @@ def endswith(self, value):
         value = self.escape_value(value)
         return u'endswith({0}, {1})'.format(self.name, value)
 
+    def contains(self, value):
+        """Extend the StringProperty with contains method"""
+        value = self.escape_value(value)
+        return u'contains({0}, {1})'.format(self.name, value)
+
+    def lacks(self, value):
+        """Does not contain"""
+        value = self.escape_value(value)
+        return u'not(contains({0}, {1}))'.format(self.name, value)
+
 
 class IntegerProperty(PropertyBase):
     """