Introduction. The aim of the study was to assess the effects of 4 months of karate training on the body composition of advanced males and females and its comparison from the preparatory and start period with the results of a control group. Material and methods. The study covered 18 kyokushin karate contestants (9 females, 9 males) from a Polish karate kyokushin club (R-research group), mean age of 22,8±4,9 years (18-33), mean BMI of 23,3±2,20 [kg/m 2 ] (19,6-27,5), mean number of years of experience of 8,3±3,36 years (5-16) and 20 individuals (10 males, 10 females; C-control group)-performing up to 1 hour of physical activity per week, mean age of 24,5±3,39 years (22-33), mean BMI of 24,1±2,71 [kg/m 2 ] (20,4-29,8). Two measurements of the body composition of athletes were made with the use of: OMRON BF 306 and BODYSTAT 1500 devices. Results. The study results show no statistically significant change in body composition in women who participate in kyokushin karate training between the first and second measurement (p>0,05), in turn, such changes were demonstrated in men when analyzed by BODYSTAT 1500: the percentage of fat mass was lower and fat free mass was higher after preparation period (p<0,01) and the percentage of total body water was higher (p<0,05). Anthropometric characteristics of athletes surveyed in both preparation and start periods show no significant differences (p>0,05). Conclusions. Anthropometric factors, type of body building, body mass index and body composition are all of great importance in a highly qualified sport like the karate. However, the large number of measurement tools, questionable repeatability of tests conditions and differences found between the sexes or ethnic discrepancies makes the evaluation and comparison analyzes of selected anthropometric indices and body composition rather difficult.