diff --git a/main/config.w32.h.in b/main/config.w32.h.in
index 27252d24c63..3939260fb35 100644
--- a/main/config.w32.h.in
+++ b/main/config.w32.h.in
@@ -45,6 +45,7 @@
 #define HAVE_MBSTR_CN 1
 #define HAVE_MBSTR_JA 1
 #define HAVE_MBSTR_KR 1
+#define HAVE_MBSTR_RU 1
 #define HAVE_MBSTR_TW 1
 
 /* Enable / Disable MySQL extension (default: enabled) */
diff --git a/win32/php4dll.dsp b/win32/php4dll.dsp
index a3fe29657f2..deda2b26cdb 100644
--- a/win32/php4dll.dsp
+++ b/win32/php4dll.dsp
@@ -923,6 +923,10 @@ SOURCE=..\ext\mbstring\mbfilter_kr.c
 # End Source File
 # Begin Source File
 
+SOURCE=..\ext\mbstring\mbfilter_ru.c
+# End Source File
+# Begin Source File
+
 SOURCE=..\ext\mbstring\mbfilter_tw.c
 # End Source File
 # Begin Source File
diff --git a/win32/php4dllts.dsp b/win32/php4dllts.dsp
index f4c27649afb..b667e90f3ea 100644
--- a/win32/php4dllts.dsp
+++ b/win32/php4dllts.dsp
@@ -513,6 +513,10 @@ SOURCE=..\ext\mbstring\mbfilter_kr.c
 # End Source File
 # Begin Source File
 
+SOURCE=..\ext\mbstring\mbfilter_ru.c
+# End Source File
+# Begin Source File
+
 SOURCE=..\ext\mbstring\mbfilter_tw.c
 # End Source File
 # Begin Source File