Basing on a field experiment carried out in the years 1996–1998 at Parczew field experimental station in split-plot dependent configuration, an attempt for improvement of seed potatoes quality was undertaken. The factors of the experiment were cultivation technologies: a) without protective treatments, b) using protective treatments; cultivars (Irys, Orlik, Arkadia, Bogna); plant density 10, 20, 30 cm in a row. The yield of tubers, its structure, share and yield of seed fraction, health of tubers estimated by PVY, PLRV, PVM, PVS, PVX infection were marked in the experiment. Cultivation technology of potato minitubers using protective treatments contributed to the limitation of PVY, PLRV and PVM tuber infection, increase of total yield, seed of potato yield, seed number und multiplication of the coefficient. Planting 160 thousands minitubers per ha caused an increase of the total yield of tubers, seed yield of tubers, seed number, multiplication coefficient, but also an increase of PVY and PVM infection.