diff --git a/layout/generic/nsBlockReflowState.cpp b/layout/generic/nsBlockReflowState.cpp
index 2e41bb8d0c06..e4e737858da7 100644
--- a/layout/generic/nsBlockReflowState.cpp
+++ b/layout/generic/nsBlockReflowState.cpp
@@ -870,7 +870,7 @@ nsBlockReflowState::FlowAndPlaceFloater(nsFloaterCache* aFloaterCache,
 
   // Enforce CSS2 9.5.1 rule [2], i.e., make sure that a float isn't
   // ``above'' another float that preceded it in the flow.
-  mY = NS_MAX(mSpaceManager->GetLowestRegionTop(), mY);
+  mY = NS_MAX(mSpaceManager->GetLowestRegionTop() + BorderPadding().top, mY);
 
   // See if the floater should clear any preceeding floaters...
   if (NS_STYLE_CLEAR_NONE != floaterDisplay->mBreakType) {
diff --git a/layout/html/base/src/nsBlockReflowState.cpp b/layout/html/base/src/nsBlockReflowState.cpp
index 2e41bb8d0c06..e4e737858da7 100644
--- a/layout/html/base/src/nsBlockReflowState.cpp
+++ b/layout/html/base/src/nsBlockReflowState.cpp
@@ -870,7 +870,7 @@ nsBlockReflowState::FlowAndPlaceFloater(nsFloaterCache* aFloaterCache,
 
   // Enforce CSS2 9.5.1 rule [2], i.e., make sure that a float isn't
   // ``above'' another float that preceded it in the flow.
-  mY = NS_MAX(mSpaceManager->GetLowestRegionTop(), mY);
+  mY = NS_MAX(mSpaceManager->GetLowestRegionTop() + BorderPadding().top, mY);
 
   // See if the floater should clear any preceeding floaters...
   if (NS_STYLE_CLEAR_NONE != floaterDisplay->mBreakType) {