The life of highly loaded vital parts of die casting dies can be successfully extended by a systematic maintenance and timely repair of damaged surfaces. It has been proved that by a regular maintenance of die parts, the cost of usually very expensive die in the price of an article can be considerably reduced. In this paper we report some of our latest results involving studies of repair surfacing of maraging steel with a Ni-Co-Mo alloy similar to the maraging steel using a CO2 laser process. The results are based on optical microstructural analyses of the surfaced layer and are supported by analyses of the micro-hardness and the residual stresses, carried out on suitably adapted flat specimens.