diff --git a/intl/uconv/public/nsIPlatformCharset.h b/intl/uconv/public/nsIPlatformCharset.h
index c9db0d7e8b8..ac8c63620f7 100644
--- a/intl/uconv/public/nsIPlatformCharset.h
+++ b/intl/uconv/public/nsIPlatformCharset.h
@@ -55,6 +55,8 @@ public:
 
   NS_IMETHOD GetCharset(nsPlatformCharsetSel selector, nsString& oResult) = 0;
 
+  NS_IMETHOD GetDefaultCharsetForLocale(const PRUnichar* localeName, PRUnichar** _retValue) = 0;
+
 };
 
 #endif /* nsIPlatformCharset_h__ */
diff --git a/intl/uconv/src/nsMacCharset.cpp b/intl/uconv/src/nsMacCharset.cpp
index f6a407f5445..0a93af75296 100644
--- a/intl/uconv/src/nsMacCharset.cpp
+++ b/intl/uconv/src/nsMacCharset.cpp
@@ -36,6 +36,8 @@ public:
   virtual ~nsMacCharset();
 
   NS_IMETHOD GetCharset(nsPlatformCharsetSel selector, nsString& oResult);
+  NS_IMETHOD GetDefaultCharsetForLocale(const PRUnichar* localeName, PRUnichar** _retValue);
+
 private:
   nsString mCharset;
 };
@@ -85,6 +87,12 @@ nsMacCharset::GetCharset(nsPlatformCharsetSel selector, nsString& oResult)
    return NS_OK;
 }
 
+NS_IMETHODIMP 
+nsMacCharset::GetDefaultCharsetForLocale(const PRUnichar* localeName, PRUnichar** _retValue)
+{
+	return NS_OK;
+}
+
 class nsMacCharsetFactory : public nsIFactory {
    NS_DECL_ISUPPORTS
 
diff --git a/intl/uconv/src/nsUNIXCharset.cpp b/intl/uconv/src/nsUNIXCharset.cpp
index 6a0a94e9585..52657b8690d 100644
--- a/intl/uconv/src/nsUNIXCharset.cpp
+++ b/intl/uconv/src/nsUNIXCharset.cpp
@@ -37,6 +37,7 @@ public:
   virtual ~nsUNIXCharset();
 
   NS_IMETHOD GetCharset(nsPlatformCharsetSel selector, nsString& oResult);
+  NS_IMETHOD GetDefaultCharsetForLocale(const PRUnichar* localeName, PRUnichar** _retValue);
 
 private:
   nsString mCharset;
@@ -89,6 +90,12 @@ nsUNIXCharset::GetCharset(nsPlatformCharsetSel selector, nsString& oResult)
    return NS_OK;
 }
 
+NS_IMETHODIMP 
+nsUNIXCharset::GetDefaultCharsetForLocale(const PRUnichar* localeName, PRUnichar** _retValue)
+{
+	return NS_OK;
+}
+
 class nsUNIXCharsetFactory : public nsIFactory {
    NS_DECL_ISUPPORTS
 
diff --git a/intl/uconv/src/nsWinCharset.cpp b/intl/uconv/src/nsWinCharset.cpp
index 0394398b223..411ae0463f3 100644
--- a/intl/uconv/src/nsWinCharset.cpp
+++ b/intl/uconv/src/nsWinCharset.cpp
@@ -23,7 +23,13 @@
 #include <windows.h>
 #include "nsUConvDll.h"
 #include "nsPlatformCharsetFactory.h"
+#include "nsIWin32Locale.h"
+#include "nsCOMPtr.h"
+#include "nsLocaleCID.h"
+#include "nsIComponentManager.h"
 
+NS_DEFINE_IID(kIWin32LocaleIID, NS_IWIN32LOCALE_IID);
+NS_DEFINE_CID(kWin32LocaleFactoryCID, NS_WIN32LOCALEFACTORY_CID);
 
 class nsWinCharset : public nsIPlatformCharset
 {
@@ -35,6 +41,7 @@ public:
   virtual ~nsWinCharset();
 
   NS_IMETHOD GetCharset(nsPlatformCharsetSel selector, nsString& oResult);
+  NS_IMETHOD GetDefaultCharsetForLocale(const PRUnichar* localeName, PRUnichar** _retValue);
 private:
   nsString mCharset;
 };
@@ -78,6 +85,41 @@ nsWinCharset::GetCharset(nsPlatformCharsetSel selector, nsString& oResult)
    return NS_OK;
 }
 
+NS_IMETHODIMP
+nsWinCharset::GetDefaultCharsetForLocale(const PRUnichar* localeName, PRUnichar** _retValue)
+{
+	nsCOMPtr<nsIWin32Locale>	winLocale;
+	LCID						localeAsLCID;
+	char						acp_name[6];
+	nsString					charset("windows-1252");
+	nsString					localeAsNSString(localeName);
+
+	//
+	// convert locale name to a code page (through the LCID)
+	//
+	nsresult result = nsComponentManager::CreateInstance(kWin32LocaleFactoryCID,nsnull,kIWin32LocaleIID,
+												getter_AddRefs(winLocale));
+	result = winLocale->GetPlatformLocale(&localeAsNSString,&localeAsLCID);
+	if (NS_FAILED(result)) { *_retValue = charset.ToNewUnicode(); return result; }
+
+	if (GetLocaleInfo(localeAsLCID,LOCALE_IDEFAULTANSICODEPAGE,acp_name,sizeof(acp_name))==0) { *_retValue = charset.ToNewUnicode(); return NS_ERROR_FAILURE; }
+
+	//
+	// load property file and convert from LCID->charset
+	//
+
+	nsAutoString property_url("resource:/res/wincharset.properties");
+	nsURLProperties *charset_properties = new nsURLProperties(property_url);
+	if (!charset_properties) { *_retValue = charset.ToNewUnicode(); return NS_ERROR_OUT_OF_MEMORY; }
+
+     nsAutoString acp_key("acp.");
+	 acp_key.Append(acp_name);
+	 result = charset_properties->Get(acp_key,charset);
+	
+	 *_retValue = charset.ToNewUnicode();
+	 return result;
+}
+
 class nsWinCharsetFactory : public nsIFactory {
    NS_DECL_ISUPPORTS
 
diff --git a/intl/uconv/tests/makefile.win b/intl/uconv/tests/makefile.win
index 70425a20575..17c7f90a625 100644
--- a/intl/uconv/tests/makefile.win
+++ b/intl/uconv/tests/makefile.win
@@ -23,7 +23,8 @@ MAKE_OBJ_TYPE = EXE
 PROG1 = .\$(OBJDIR)\convperf.exe
 PROG2 = .\$(OBJDIR)\nsTestUConv.exe
 PROG3 = .\$(OBJDIR)\nsconv.exe
-PROGRAMS = $(PROG1) $(PROG2) $(PROG3)
+PROG4 = .\$(OBJDIR)\plattest.exe 
+PROGRAMS = $(PROG1) $(PROG2) $(PROG3) $(PROG4)
 
 LCFLAGS=-DUSE_NSREG
 
@@ -47,3 +48,4 @@ clobber::
 $(PROG1): $(OBJDIR) convperf.cpp
 $(PROG2): $(OBJDIR) nsTestUConv.cpp
 $(PROG3): $(OBJDIR) nsconv.cpp
+$(PROG4): $(OBJDIR) plattest.cpp
diff --git a/intl/uconv/tests/plattest.cpp b/intl/uconv/tests/plattest.cpp
new file mode 100644
index 00000000000..b88bfb7638a
--- /dev/null
+++ b/intl/uconv/tests/plattest.cpp
@@ -0,0 +1,63 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * The contents of this file are subject to the Netscape Public License
+ * Version 1.0 (the "License"); you may not use this file except in
+ * compliance with the License.  You may obtain a copy of the License at
+ * http://www.mozilla.org/NPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.  See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ *
+ * The Initial Developer of the Original Code is Netscape Communications
+ * Corporation.  Portions created by Netscape are Copyright (C) 1998
+ * Netscape Communications Corporation.  All Rights Reserved.
+ */
+#include "nsIPlatformCharset.h"
+#include "nsILocaleService.h"
+#include "nsCOMPtr.h"
+#include "nsLocaleCID.h"
+#include "nsIComponentManager.h"
+#include <stdio.h>
+
+NS_DEFINE_IID(kLocaleServiceIID,NS_ILOCALESERVICE_IID);
+NS_DEFINE_CID(kLocaleServiceCID,NS_LOCALESERVICE_CID);
+NS_DEFINE_IID(kPlatformCharsetIID,NS_IPLATFORMCHARSET_IID);
+
+int
+main(int argc, const char** argv)
+{
+	nsCOMPtr<nsILocaleService>		locale_service;
+	nsCOMPtr<nsILocale>				locale;
+	nsCOMPtr<nsIPlatformCharset>	platform_charset;
+	nsString						locale_category("NSILOCALE_MESSAGES");
+	PRUnichar*						category_value, *charset;
+	nsString						categoryAsNSString, charsetAsNSString;
+
+	nsresult rv = nsComponentManager::CreateInstance(NS_PLATFORMCHARSET_PROGID,NULL,kPlatformCharsetIID,getter_AddRefs(platform_charset));
+	rv = nsComponentManager::CreateInstance(kLocaleServiceCID,NULL,kLocaleServiceIID,getter_AddRefs(locale_service));
+	if (NS_FAILED(rv)) return -1;
+
+	rv = locale_service->GetSystemLocale(getter_AddRefs(locale));
+	if (NS_FAILED(rv)) return -1;
+
+	rv = locale->GetCategory(locale_category.GetUnicode(),&category_value);
+	if (NS_FAILED(rv)) return -1;
+
+	rv = platform_charset->GetDefaultCharsetForLocale(category_value,&charset);
+	if (NS_FAILED(rv)) return -1;
+
+	charsetAsNSString = charset;
+	categoryAsNSString = category_value;
+	printf("DefaultCharset for %s is %s\n",categoryAsNSString.ToNewCString(),charsetAsNSString.ToNewCString());
+
+	categoryAsNSString = "en-US";
+	rv = platform_charset->GetDefaultCharsetForLocale(categoryAsNSString.GetUnicode(),&charset);
+	if (NS_FAILED(rv)) return -1;
+
+	charsetAsNSString = charset;
+	printf("DefaultCharset for %s is %s\n",categoryAsNSString.ToNewCString(),charsetAsNSString.ToNewCString());
+
+	return 0;
+}
\ No newline at end of file