The paper presents a statistical analysis of weight and diameter of ker-nel obtained for eight investigated winter wheat cultivars. Preliminary analyses of experimental results, such as compliance with a normal dis-tribution, equality of variance for particular cultivars, and occurrence of outliers proved that there is no justification for the use of a traditional one-way analysis of variance for verification of hypotheses according to which weight and diameter of grains of the investigated winter wheat cultivars do not differ. A nonparametric Kruskal-Wallis test was used for verification of hypotheses which based on the experimental results enabled to reject both hypotheses. Further, simultaneous average weight and diameters of grain of the investigated cultivars were com-pared with the use of Nemenyi-Dunn test. The applied test enabled to conclude which cultivars had a significantly higher weight than the oth-ers. Analogous comparisons were carried out for the diameter of kernels of the investigated winter wheat cultivars.