diff --git a/include/boost/numeric/ublas/io.hpp b/include/boost/numeric/ublas/io.hpp
index d84c8fad..795dd9bd 100644
--- a/include/boost/numeric/ublas/io.hpp
+++ b/include/boost/numeric/ublas/io.hpp
@@ -15,6 +15,7 @@
 
 // Only forward definition required to define stream operations
 #include <iosfwd>
+#include <sstream>
 #include <boost/numeric/ublas/matrix_expression.hpp>