diff --git a/doc/src/sgml/install-windows.sgml b/doc/src/sgml/install-windows.sgml
index ba794b8c93..7a38a49ee9 100644
--- a/doc/src/sgml/install-windows.sgml
+++ b/doc/src/sgml/install-windows.sgml
@@ -155,6 +155,10 @@ $ENV{PATH}=$ENV{PATH} . ';c:\some\where\bison\bin';
   command (msbuild or vcbuild):
 <programlisting>
 $ENV{MSBFLAGS}="/m";
+ <para>
+  To build Postgres in 32 bits, set Platform before build command:
+<programlisting>
+$ENV{MSBFLAGS}="/p:Platform="Win32";
 </programlisting>
  </para>