A forecast system of sea waves has been developed and has been operatively running since June 2013. The forecasts are performed over the entire Mediterranean basin with a horizontal resolution of about 3.5 km and, at a higher resolution, over ten subbasins around the Italian coasts. The forecasts performed over the entire basin are essential in order to provide the boundary conditions to the children models. The intensity of wave motion depends both on local wind conditions and on waves propagation from neighboring areas. The forecast system is here described along with the validation of the wave heights, performed by comparing them with the measurements from Rete Ondametrica Nazionale.