The studies were carried out in the period of 2005–2007. The tillage systems were taken into consideration including the following experimental factors: I factor – cultivation system – a) simplified tillage without ploughing, b) conventional tillage with ploughing, c) direct sowing; II factor – stubble height – a) low stubble, b) high stubble; III – factor – winter wheat varieties: Mewa, Rapsodia and Legenda. Winter oilseed rape was a previous crop to winter wheat during the whole experimental period. At the milk and wax maturity of grains the observations of winter wheat plants were performed on the infection by complex of stem base diseases. The mutual relations among the experimental factors, i.e. the number of diseased stems, height of stubble, tillage systems and winter wheat cultivars were subjected to the log-linear analysis. It was stated no interaction between stubble height and the intensity of stem base diseases. Direct sowing caused a slightly higher intensity of the stem base diseases. The variety Rapsodia was more susceptible to stem base diseases, as compared to the other varieties.