diff --git a/content/base/src/nsDocument.cpp b/content/base/src/nsDocument.cpp
index fa8de27f0f5..9dc101a702f 100644
--- a/content/base/src/nsDocument.cpp
+++ b/content/base/src/nsDocument.cpp
@@ -9608,6 +9608,14 @@ nsIDocument::DocSizeOfExcludingThis(nsWindowSizes* aWindowSizes) const
                                     &aWindowSizes->mLayoutPresContext);
   }
 
+  aWindowSizes->mPropertyTables +=
+    mPropertyTable.SizeOfExcludingThis(aWindowSizes->mMallocSizeOf);
+  for (PRUint32 i = 0, count = mExtraPropertyTables.Length();
+       i < count; ++i) {
+    aWindowSizes->mPropertyTables +=
+      mExtraPropertyTables[i]->SizeOfExcludingThis(aWindowSizes->mMallocSizeOf);
+  }
+
   // Measurement of the following members may be added later if DMD finds it
   // is worthwhile:
   // - many!
diff --git a/content/base/src/nsPropertyTable.cpp b/content/base/src/nsPropertyTable.cpp
index cb0adeeef4d..98ceb81d465 100644
--- a/content/base/src/nsPropertyTable.cpp
+++ b/content/base/src/nsPropertyTable.cpp
@@ -52,6 +52,8 @@ public:
     return mName == aPropertyName;
   }
 
+  size_t SizeOfIncludingThis(nsMallocSizeOfFun aMallocSizeOf);
+
   nsCOMPtr<nsIAtom>  mName;           // property name
   PLDHashTable       mObjectValueMap; // map of object/value pairs
   NSPropertyDtorFunc mDtorFunc;       // property specific value dtor function
@@ -337,6 +339,26 @@ nsPropertyTable::PropertyList::DeletePropertyFor(nsPropertyOwner aObject)
   return true;
 }
 
+size_t
+nsPropertyTable::PropertyList::SizeOfIncludingThis(nsMallocSizeOfFun aMallocSizeOf)
+{
+  size_t n = aMallocSizeOf(this);
+  n += PL_DHashTableSizeOfExcludingThis(&mObjectValueMap, NULL, aMallocSizeOf);
+  return n;
+}
+
+size_t
+nsPropertyTable::SizeOfExcludingThis(nsMallocSizeOfFun aMallocSizeOf) const
+{
+  size_t n = 0;
+
+  for (PropertyList *prop = mPropertyList; prop; prop = prop->mNext) {
+    n += prop->SizeOfIncludingThis(aMallocSizeOf);
+  }
+
+  return n;
+}
+
 /* static */
 void
 nsPropertyTable::SupportsDtorFunc(void *aObject, nsIAtom *aPropertyName,
diff --git a/content/base/src/nsPropertyTable.h b/content/base/src/nsPropertyTable.h
index b66e511ff3e..4a35b9a6286 100644
--- a/content/base/src/nsPropertyTable.h
+++ b/content/base/src/nsPropertyTable.h
@@ -177,6 +177,8 @@ class nsPropertyTable
 
   class PropertyList;
 
+  size_t SizeOfExcludingThis(nsMallocSizeOfFun aMallocSizeOf) const;
+
  private:
   NS_HIDDEN_(void) DestroyPropertyList();
   NS_HIDDEN_(PropertyList*) GetPropertyListFor(nsIAtom *aPropertyName) const;
diff --git a/dom/base/nsWindowMemoryReporter.cpp b/dom/base/nsWindowMemoryReporter.cpp
index ecd31cb603e..8f80f4563e8 100644
--- a/dom/base/nsWindowMemoryReporter.cpp
+++ b/dom/base/nsWindowMemoryReporter.cpp
@@ -177,6 +177,11 @@ CollectWindowReports(nsGlobalWindow *aWindow,
          "Memory used by the comment nodes in a window's DOM.");
   aWindowTotalSizes->mDOMCommentNodes += windowSizes.mDOMCommentNodes;
 
+  REPORT("/property-tables",
+         windowSizes.mPropertyTables,
+         "Memory used for the property tables within a window.");
+  aWindowTotalSizes->mPropertyTables += windowSizes.mPropertyTables;
+
   REPORT("/style-sheets", windowSizes.mStyleSheets,
          "Memory used by style sheets within a window.");
   aWindowTotalSizes->mStyleSheets += windowSizes.mStyleSheets;
@@ -328,6 +333,11 @@ nsWindowMemoryReporter::CollectReports(nsIMemoryMultiReporterCallback* aCb,
          "Memory used for DOM comment nodes within windows. "
          "This is the sum of all windows' 'dom/comment-nodes' numbers.");
 
+  REPORT("window-objects/property-tables",
+         windowTotalSizes.mPropertyTables,
+         "Memory used for property tables within windows. "
+         "This is the sum of all windows' 'property-tables' numbers.");
+
   REPORT("window-objects/style-sheets", windowTotalSizes.mStyleSheets, 
          "Memory used for style sheets within windows. "
          "This is the sum of all windows' 'style-sheets' numbers.");
diff --git a/dom/base/nsWindowMemoryReporter.h b/dom/base/nsWindowMemoryReporter.h
index a953204d7f5..5e155dc6651 100644
--- a/dom/base/nsWindowMemoryReporter.h
+++ b/dom/base/nsWindowMemoryReporter.h
@@ -39,6 +39,7 @@ public:
   size_t mLayoutStyleSets;
   size_t mLayoutTextRuns;
   size_t mLayoutPresContext;
+  size_t mPropertyTables;
 };
 
 /**