In this study, exercise performance was evaluated in 259 healthy adolescents by using some tests. The purpose of the study was to investigate exercise performance and cardiorespiratory capacity in both adolescent boys and girls. The following tests were applied to all children: ball throw with right and left hands, vertical jump, long jump without prior motion, pull up (repetition number), flexibility, and agility (set repetition number) tests. Additionally, heart rate and systolic and diastolic blood pressures were measured. Applied spirometric tests were as follows: vital capacity, forced vital capacity, forced expiration volume in the first second, ventilation volume, maximum volunteer ventilation and respiration frequency. This study found that heart rate was statistically significantly higher in females than males (p < .05). There was also a statistically significant difference in vital capacity, forced vital capacity and forced expiratory volume in the first second (in both measured and predicted values) between males and females (p < .05). Additionally, it was found that there were statistically significant differences in the 60 and 200 meters races, maximal pull up, maximal sit up. vertical jump, standing long jump, ball throwing with right hand, horizontal bar, and agility between the male and female groups (p < .05). In conclusion. the findings showed that although females were superior in the 60 and 200 meter race, males were superior in agility. horizontal bar, hall throwing with right hand, long jump, and vertical jump.