diff --git a/src/converter.hh b/src/converter.hh
index d3d910a57b5a2b3b9165d383ae95584aa37d757a..7c953b68221fa3f4a1700f96e1da7452adbf7371 100644
--- a/src/converter.hh
+++ b/src/converter.hh
@@ -109,7 +109,7 @@ namespace dynamicgraph
   {
 
     //TODO: Confirm Ros Matrix Storage order. It changes the RosMatrix to ColMajor.
-    dst.width = src.rows ();
+    dst.width = (unsigned int)src.rows ();
     dst.data.resize (src.cols () * src.rows ());
     for (int i = 0; i < src.cols () * src.rows (); ++i)
       dst.data[i] =  src.data()[i];