diff --git a/NEWS.txt b/NEWS.txt
index b5df75f..5382e51 100644
--- a/NEWS.txt
+++ b/NEWS.txt
@@ -38,6 +38,8 @@ Bug fixes
   Anjargolian).
 - Fix issues with blurry 1px border when some measures aren't integer
   (reported by Ara Anjargolian).
+- Fix bug with formats in the data processor (reported by Peter Hull,
+  issue 534).
 
 
 Flot 0.7
diff --git a/jquery.flot.js b/jquery.flot.js
index 65ebe45..b7ff6ee 100644
--- a/jquery.flot.js
+++ b/jquery.flot.js
@@ -633,6 +633,7 @@
                 s = series[i];
                 points = s.datapoints.points,
                 ps = s.datapoints.pointsize;
+                format = s.datapoints.format;
 
                 var xmin = topSentry, ymin = topSentry,
                     xmax = bottomSentry, ymax = bottomSentry;