Background: Tennis is characterized with short and intermittent efforts of an altering intensity and time where numerous factors determine the achieved success. Some of them include human's morphological body build, motor abilities and efficiency of the energetic systems. Both motor abilities and physical capacity appear to be particularly significant due to the unpredictable time and weather situation of the tournaments. The purpose of this study was to determine the relationship between body composition, aerobic capacity and the balance in young tennis players at rest and during fatigue triggered by an endurance test. Moreover, we tried to find the correlation between the tennis ranking position and the balance.Material/Methods: Well-trained 16 young tennis players (15 and 17 years old, singles national ranking 3-39, average training experience of 9 years) took part in this study. They were assigned to two groups according to their age - 15 TG and 17 TG. Participants completed the same battery of body composition, aerobic, and body balance assessments. Body balance measurement was repeated twice - before and after the aerobic assessment.Results: The main finding of this study points out the body balance to be a motor ability influencing results achieved in the specific tennis drill. This connection was observed in both of the tested groups; however, it was particularly significant within 17 TG.Conclusions: The presented study does not point out the main factor to focus on when conducting a career of a professional tennis player regardless of the numerous tests and measurements included in the analysis observed. Interesting correlations may suggest that for the players in a developmental age it is speed and balance that ought to be more intensively developed.