The aim of the present work is to determine the influence of borided surface layers on the friction parameter in the work of sliding pairs in the I.C. engine. The tribological evaluation included pack-borided and laser-borided surface layers deposited on rocker arm, piston pin and pin of crankshaft. The tests were performed in the generator set equipped with one-cylinder 4-stroke carburettor Robin Subaru engine. The wear of the elements of the combustion engine demonstrated that the process of boronizing has an important influence on the decrease of wear of the borided element of the friction pair.