A field experiment was conducted at the Agricultural Experiment Station in Pawlowice near Wrocław (51°09’ N; 17°06’ E) in the years 2004-2006. It was investigating the reaction of three silage maize hybrids to different weed control treatments (control, mechanical, chemical). The aim of this research was to estimate the efficiency of different weed control treatments on maize hybrids yield harvested for silage. Those weed control treatments had an influence on maize density. In control and after mechanical weed treatment maize density was significantly lower than after herbicide spraying. Mechanical as well as chemical weed control had a favorable influence on maize yield and its structure. Mechanical and chemical weed treatment had a similar effect on maize dry matter yield. (8.5 and 8.3 t·ha^-1, respectively). The lowest yield was obtained from control (without any weed control treatment) only 3.1 t·ha^-1. Crude protein yield and feed units for lactation (UFL) were also higher after mechanical and chemical weed treatment. Weed biomass depended on weed control methods. Without any weed control methods the weed biomass reached 6.2 t D.M.· ha^-1, much higher than after mechanical (3.8 t D.M.· ha^-1) and chemical weed control (2.7 t D.M.· ha^-1). Maize hybrids significantly differed in their den sity and dry matter yield. Iman had the highest plant density per ha. Dry matter yield from Wilga hybrids (5.1 t·ha^-1) was significantly lower than that from Iman (7.7 t·ha^-1) and Blask (7.0 t·ha^-1). There were no significant differences in the other features between the hybrids.

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