diff --git a/src/osgPlugins/hdr/hdrwriter.cpp b/src/osgPlugins/hdr/hdrwriter.cpp
index 25432b553..1644074c3 100644
--- a/src/osgPlugins/hdr/hdrwriter.cpp
+++ b/src/osgPlugins/hdr/hdrwriter.cpp
@@ -30,6 +30,7 @@
 #include "hdrwriter.h"
 
 #include <sstream>
+#include <ostream>
 #include <string>
 #include <math.h>
 #include <ctype.h>
diff --git a/src/osgPlugins/hdr/hdrwriter.h b/src/osgPlugins/hdr/hdrwriter.h
index e86804d23..8374ba9c5 100644
--- a/src/osgPlugins/hdr/hdrwriter.h
+++ b/src/osgPlugins/hdr/hdrwriter.h
@@ -26,6 +26,7 @@
 
 #include <osg/Image>
 
+#include <iosfwd>
 #include <math.h>
 
 class HDRWriter {