diff --git a/RELEASE_NOTES.rst b/RELEASE_NOTES.rst
index 0f4327e01..9f2784c03 100644
--- a/RELEASE_NOTES.rst
+++ b/RELEASE_NOTES.rst
@@ -51,6 +51,8 @@ Release notes
 * The PDQ(2/3) driver has been removed and is now being maintained out-of tree
   at https://github.com/m-labs/pdq. All SPI/USB driver layers, Mediator,
   CompoundPDQ and examples/documentation has been moved.
+* The results keys start_time and run_time are now stored as doubles, rather
+  than ints.
 
 
 2.4
diff --git a/artiq/master/worker_impl.py b/artiq/master/worker_impl.py
index fb7e4831c..3d6153603 100644
--- a/artiq/master/worker_impl.py
+++ b/artiq/master/worker_impl.py
@@ -287,8 +287,8 @@ def main():
                     dataset_mgr.write_hdf5(f)
                     f["artiq_version"] = artiq_version
                     f["rid"] = rid
-                    f["start_time"] = int(start_time)
-                    f["run_time"] = int(run_time)
+                    f["start_time"] = start_time
+                    f["run_time"] = run_time
                     f["expid"] = pyon.encode(expid)
                 put_object({"action": "completed"})
             elif action == "examine":