The purpose of the research was to determine the influence of cultivar, malting time and thickness of brewing barley grains on selected properties of laboratory worts, which were obtained from 4-, 5- and 6- day malts of the Pilzen type with maize grits addition. The materials used in this study were 10 cultivars of barley grain (Class, Blask, Riviera, Lailla, Hanka, Sebastian, Bolina, Philadelphia, Tolar, Stratus), from growing season 2005 and maize grits of 500-1250 µm granulation. For malts produced for 4, 5 and 6 days grain of thickness in the range from 2.5 to 2.8 mm and over 2.8 mm was used. Malting was carried out in laboratory conditions, typical of the production of Pilzen type malts. Maize grits, in the amount of 20% of charge, was gelatinized at the temperature of 90°C for 10 minutes, in the ratio of grain to water 1:5. Gelatinized maize grits was mixed with malt and mashed using congress method. There were determined: extract content, colour, viscosity, apparent final attenuation and total soluble nitrogen content, and free amino nitrogen in laboratory worts. Extractivity of malt and mashing composition of malt and maize grits were calculated. Control wort, produced only from malt, served as a material for comparison. It was stated that cultivar have significant effect on majority properties of worts. The addition of 20% of maize grits caused an increase in mash extractivity and worts viscosity, and also a decrease in colour intensity, degree of apparent final attenuation and content of total soluble nitrogen and free amino nitrogen. Worts obtained from malts, which were produced from barley grains of differential thickness, were differed as regards only colour intensity. 5-days malting time of brewing barley grain was contributed to the best technological parameters of worts, in comparison to 4- and 6-days malting time.