An attempt to define quantitative relationships between the attack of common scab on 21 varieties of potatoes and selected elements of weather conditions was undertaken. The analysis was based on a field experiment carried out on podzolic soil of loamy sand in Jabłoń, Biala Podlaska voivodeship, Eastern Poland, in the years 1983 - 1987. It was revealed that the percentage of tubers with common scab more than the degree of the infection was determined by meteorological conditions.