Investigation of connective tissue dysplasia (CTD) role in the forming of cardiovascular system (CS) adaptive abilities to the physical load in young athletes. Thirty students (mean age19,6 ± 3,14), members of male (11 athletes) and female (19) basketball teams of UrFU under-went the maximum exercise performance treadmill-test. According to the echocardiography data, all athletes had the false tendons in left ventricle as a cardiac phenotypic manifestation of CTD. The extent of CTD development was assessed by hypermobility of joints with use the Beighton scale. CS response to the stress-test was evaluated by heart rate and blood pressure changes and further calculations of standard indices of cardiac functional reserve. We found that young basketball-players with CTD had satisfactory level of exercise performance, though maximum work efficiency of male athletes was significantly higher (16,7 ± 1,9 METs), than female ones (15,1 ± 1,5 METs). At the same time, the CS adaptive source appeared to be at significantly higher level in male athletes. Based on the significant correlations between the CTD Beighton index and a number of CS reserve indices, we concluded that the lower the extent of CTD development, the higher the CS adaptive abilities of young basketballplayers with CTD.