diff --git a/applications/osgconv/osgconv.cpp b/applications/osgconv/osgconv.cpp
index dfcce9e92..286bddd18 100644
--- a/applications/osgconv/osgconv.cpp
+++ b/applications/osgconv/osgconv.cpp
@@ -25,6 +25,16 @@
 
 #include "OrientationConverter.h"
 
+#if (_MSC_VER >= 1400) // Visual Studio 2005
+#include <sstream>
+int setenv(const char *name, const char *value, int /*rewrite*/)
+{
+    std::stringstream sstr;
+    sstr<<name<<'='<<value;
+    return _putenv(sstr.str().c_str());
+}
+#endif
+
 typedef std::vector<std::string> FileNameList;
 
 
@@ -450,13 +460,12 @@ int main( int argc, char **argv )
         return 1;
     }
 
-#ifndef _WIN32
     std::string options;
     while(arguments.read("--optimizer",options))
     {
         setenv("OSG_OPTIMIZER",options.c_str(),1);
     }
-#endif
+
 
     FileNameList fileNames;
     OrientationConverter oc;