Assessment of human body composition has stimulated the need for an understanding of available methodologies of estimating fat-free mass and percent body fat. In our study, we found statistical significant changes of body composition evaluated by multi-frequency bioelectrical analysis in a group of athletes following creatine supplementation. These results are consistent with literature i.e. supplemented creatine effects osmolality of cell's membranes which leads to increased intracellular water retention. Multi-frequency BIA can be considered to be an accurate and sensitive method for assessment of human body composition.