The experiment was carried out in 2005-2007 at the Education and Research Station Krasne near Rzeszów in the brown soil formed from loess, classified as the good wheat complex. The aim of this study was to estimate the effect of four sowing densities on the number, air-dry weight and species composition of weeds and the grain yield of winter wheat under conditions of two levels of agricultural practices. Intensification of level of wheat agricultural practices significantly reduced both the numbers of weeds – on average by 39.2 pcs·m^-2 (49.4%) and their air-dry weight (by 46.4%). An effect of the number of sown wheat grains on weed density was not proved statistically, but the dry weight of weeds from plots with the highest sowing density was less (by 50.5%) than from the plots where sowing density was 250 grains·m^-2. Wheat cultivation at intensive level of agricultural practices resulted in an increase in grain yield in the years of the study from 0.49 to 0.82 t·ha^-1. The sowing 450 and 550 grains·m^-2 provided the highest grain yields, 6.51 and 6.79 t·ha^-1; respectively; a difference in the yield level between those densities amounted to 4.1% and was statistically insignificant. The lowest yield of wheat grain 4.84 t·ha^-1 was found under conditions of the smallest sowing density.

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