diff --git a/lisa/trace.py b/lisa/trace.py
index 6112a190d735362910d051ca25542ce0a74180f2..f51b87e243a015ce44892b6b3fe23a40438a6b33 100644
--- a/lisa/trace.py
+++ b/lisa/trace.py
@@ -535,7 +535,7 @@ class Trace(Loggable, TraceBase):
                  the last time they ran in the current trace
         """
         try:
-            return self._tasks_by_pid.ix[pid].values[0]
+            return self._tasks_by_pid.loc[pid].values[0]
         except KeyError:
             return None