diff -r cefe52608b67 javafx-ui-charts/src/javafx/scene/chart/BarChart.java
--- a/javafx-ui-charts/src/javafx/scene/chart/BarChart.java	Tue Jul 10 20:22:00 2012 -0400
+++ b/javafx-ui-charts/src/javafx/scene/chart/BarChart.java	Wed Jul 11 16:50:59 2012 -0700
@@ -256,7 +256,9 @@
              item.getNode().getStyleClass().add("negative");
          } else if (currentVal < 0 && barVal > 0) { // going from negative to positive
              // remove style class negative
-             item.getNode().getStyleClass().add("negative");
+             // RT-21164 upside down bars: was adding "negative" styleclass
+             // instead of removing it; when going from negative to positive
+             item.getNode().getStyleClass().remove("negative");
          }
     }
     
@@ -314,6 +316,12 @@
             if (shouldAnimate()) {
                 animateDataAdd(item, bar);
             } else {
+                // RT-21164 check if bar value is negative to add "negative" style class 
+                double barVal = (orientation == Orientation.VERTICAL) ? ((Number)item.getYValue()).doubleValue() :
+                        ((Number)item.getXValue()).doubleValue();
+                if (barVal < 0) {
+                    bar.getStyleClass().add("negative");
+                }
                 getPlotChildren().add(bar);
             }
         }