The use of laser energy in material processing for boring, cutting and welding has been state of the art for many years . The good focussing ability of the laser allows power densities that are hardly possible with conventional welding processes. Thus, the desired component processing can be carried out on a limited area with low overall power where component and material are subjected to minimum thermal loading. The laser build-up welding process which is particularly suited for low distortion applications, as well as materials that are difficult to weld using conventional methods, is explained in detail. Co2 laser, nd:yag laser and diode laser as established beam sources in laser material processing are compared with newer, innovative beam sources like the fiber laser and disk laser that have been developed in the recent years. Where the possible spectrum of use ranges from small parts to large components weighing tons, the need for a universal handling system is discussed together with laser safety issues. Several industrial applications for laser build-up welding are presented.