Abstract Laser cutting of copper-based alloy sheets is very difficult due to their high reflectivity, which can be modified with graphitization. The optimal parameters for a 2.5 mm thick brass sheet were determined by examining the laser beam parameter variations and the laser cut kerfs. The best characteristics of kerfs were obtained when the surface was graphitized, the laser frequency was 200 Hz, the applied laser speed was 1400mm/min on 2500 W power and the focal point was under the surface by 0.8 mm. The applied working gas was nitrogen.