diff -r 5dc02b23752f -r 3e2da88830cd qmake/generators/win32/msvc_objectmodel.cpp
--- a/qmake/generators/win32/msvc_objectmodel.cpp	Tue Jul 06 15:10:48 2010 +0300
+++ b/qmake/generators/win32/msvc_objectmodel.cpp	Wed Aug 18 10:37:55 2010 +0300
@@ -674,6 +674,12 @@
             if(third == 'd')
                 RuntimeLibrary = rtMultiThreadedDebug;
             break;
+        } else if (second == 'P') {
+            if (config->CompilerVersion >= NET2005)
+                AdditionalOptions += option;
+            else
+                warn_msg(WarnLogic, "/MP option is not supported in Visual C++ < 2005, ignoring.");
+            break;
         }
         found = false; break;
     case 'O':