The publication deals with the measurement and evaluation of roughness parameters by means of laser profiling, and its main task is to determine the effect of selecting the internal gain adjustment (Gain mode) on measured roughness values of the surface treated by the water beam technology. The publication details the software, hardware, and other parts of the device designed to measure the roughness of different types of surfaces. It further describes the behavior of individual parts of the apparatus as a whole and methods of measuring the roughness of the surface along a defined profile section by means of the triangulation principle of laser profiling. The measured sample was cut by a thick (rough) cut at pressure of 380 MPa. As an abrasive, the Australian Grenade with the grain Mesh 50 was used.The experiment was carriedout at the Faculty of Production Technologies in theLaboratory of Roughness Measurement at the Department of technical systems design and monitoring in Prešov. Measurement of surface roughness parameters was performed on an optical measuring system to control surface parameters and the contact roughness meter Mitutyo SJ400.