In this study, 304 stainless steel and AISI 1050 carbon steel have been cut by plasma and under water plasma arc methods. Surface roughness values of the surface obtained after cutting and hardness values from the other surface to the core of the specimen were measured at specific intervals. Effects of these two systems to the material were investigated by evaluating the obtained results. The best results of surface roughness values were determined with the speeds proposed by the manufacturer. It was observed that the surface roughness values increased on cuttings carried out in the upper and lower limits. In addition, it was determined that the hardness decreased from the outer surface to the core while the hardness increased in the areas near to the outer surface affected by high temperature which was generated by cutting operations.