Article deals with monitoring and optimization of roughness reduction procedure used for preparation of samples for nanoindentation tests. The aim of the research was to measure roughness reduction effect of various combination of grindstones, polishing time, pressure and speed. Suitable procedure with respect to time and cost for three different materials was proposed. For porous materials trabecular bone was chosen, fibre composite as and asbestos-free plates compact ones. Roughness measurement was performed by contactless method using a confocal microscope. Number of grinding steps was reduced and optimal forces and times of grinding were estimated.