The experiment was conducted in the years 2008–2010 at the Experimental Station of the Faculty of Agricultural Sciences in Zamo , University of Life Sciences in Lublin. The following factors were analysed in the experiment: I. Cultivation method – sole cropping and strip cropping, which consisted in the cultivation of three plants: dent maize, common bean, and spring barley, in adjacent strips with a width of 3.3 m; II. Weed control methods – mechanical and chemical. The subject of the research was weed infestation of the 'Celio' variety of dent maize, the 'Aura' variety of common bean, and the 'Start' variety of spring barley. Weed infestation of the crops was assessed two weeks before harvesting by determining the species composi- tion as well as the number and dry weight of weeds. The dominant weed species in maize, common bean and spring barley were Echinochloa crus-galli, Chenopodium album and Galinsoga parviflora, constituting from 58% to 70% of the total number of weeds. Strip cropping clearly reduced the number of weeds per unit area in all the cultivated species and dry weight of aboveground parts produced by them in common bean and maize crops. The limiting effect of strip cropping on the weed infestation parameters was particularly clear in combination with the mechanical weed control method.