diff --git a/cassandra/cqltypes.py b/cassandra/cqltypes.py
index bf48724b..d023350b 100644
--- a/cassandra/cqltypes.py
+++ b/cassandra/cqltypes.py
@@ -439,6 +439,8 @@ cql_time_formats = (
     '%Y-%m-%d'
 )
 
+_have_warned_about_timestamps = False
+
 
 class DateType(_CassandraType):
     typename = 'timestamp'
@@ -482,6 +484,20 @@ class DateType(_CassandraType):
             if type(v) not in _number_types:
                 raise TypeError('DateType arguments must be a datetime or timestamp')
 
+            if not _have_warned_about_timestamps:
+                global _have_warned_about_timestamps
+                _have_warned_about_timestamps = True
+                warnings.warn("timestamp columns in Cassandra hold a number of "
+                    "milliseconds since the unix epoch.  Currently, when executing "
+                    "prepared statements, this driver multiplies timestamp "
+                    "values by 1000 so that the result of time.time() "
+                    "can be used directly.  However, the driver cannot "
+                    "match this behavior for non-prepared statements, "
+                    "so the 2.0 version of the driver will no longer multiply "
+                    "timestamps by 1000.  It is suggested that you simply use "
+                    "datetime.datetime objects for 'timestamp' values to avoid "
+                    "any ambiguity and to guarantee a smooth upgrade of the "
+                    "driver.")
             converted = v * 1e3
 
         return int64_pack(long(converted))