The article presents the results of research on laser machinability of materials. The research has been carried out on pure substances, namely C, Zn, Ti, Si, Al, Ni, Cu, Fe, Cr, as well as different types of steel, cast iron, bronze, brass and titanium alloys. A diode-pumped solid-state Ns:YAG laser with a medium output power of 50 W has been used as the radiation source. Based on experimental results, a method for defining and evaluating laser machinability of materials has been proposed, including the classification of materials in corresponding machinability classes. The definition method is based on the crystal lattice type of the material. The impact of working speed and laser pulse frequency on machinability has been assessed.