abstract: The paper deals with studies on the influence of various tillage systems and depth on winter wheat weed infestation. The experiment, carried out in 2001-2003, included three-field crop rotation system: potato – winter wheat – soybean. In no-plough system, ploughing was omitted and replaced by rearing and additionally using a set consisting of spring-tine harrow and cage roller. Depending on tillage system, ploughing or harrowing to a various depths was made. The three-year studies revealed that no-plough tillage significantly increased number and air-dried weight of weeds in winter wheat canopy as compared to ploughed objects. Air-dried weed weight was also significantly higher at deep vs. shallow tillage. Replacement of ploughing with harrowing caused apparent increase of two dominating short-term species population: Echinochloa crus-galli and Viola arven-sis. More shallow tillage resulted in a decrease of a majority of weed populations dominating in winter wheat canopy.