The experiment conducted in 2002-2004 and located on experimental fields owned by the Institute of Soil Science and Plant Cultivation determined the effect of pre-germination of organically grown six cultivars (Bard, Bila, Baszta, Wolfram, Wawrzyn, Bzura) of potato seed tubers on occurrence of common scab (Streptomyces scabies) and dry rot of tubers (Fusarium spp.). Common scab was observed each year on all examined potato cultivars, but its intensity varied. The least number of symptoms showed Wawrzyn cv., while Wolfram cv. - the highest. Pre-germination of seed tubers significantly reduced both the percentage and disease index (DI) calculated for S. scabies, with the exception for Wawrzyn and Bard cvs. Symptoms of dry rot of tubers (Fusarium spp.) were noted in higher intensity in 2004 on Bzura cv. (5.8%) and significantly more symptoms were observed on pre-germinated potato tubers.