The studies conducted in two different localities revealed variable time of occurrence and severity level of potato early blight (Alternaria spp.). Each year at Stare Olesno the early blight caused considerable destruction of potato plants (90.2%-95.4%) while at Bonin the disease severity differed in particular years and ranged from 50.0% to 97.5% of destructed plants at the end of the growing season. Field trials showed good efficacy of fungicides selected for controlling the early blight compared with an untreated control. Spraying with fungicides limited development of the disease and increased tuber yield in the range from 21.9% to 60.9% for Bonin and from 13.0% to 101.9% for Stare Olesno surveys. The mixture of zoxamide with mancozeb showed the greatest efficacy.