Problem statement: The assessment of players' physical attributes such as explosive power has been relevant for players' selection and talent identification in youth football. Among individual features, the literature describes a high positive correlation between explosive leg power (countermovement – CMJ, and squat jump – SJ) and superior levels of sports performance. Purpose: The aims of this study were twofold: 1) to investigate the effects of chronological age, body composition, and functional capacities on the CMJ and SJ performance; and (2) to develop a regression equation using easy-field tests to estimate CMJ and SJ performance. Approach: The sample was composed of 161 male football players (age = 15.8 ± 1.7 years, height = 170.7 ± 8.5 cm, body mass = 63.6 ± 10.1 kg). The calf skinfold thickness was measured as a specific body composition indicator. Strength tests included sit-ups, handgrip, CMJ and SJ heights. Linear speed and agility (T-test) were also measured. Results: Calf skinfold, handgrip, linear speed (35 m) and change of direction speeds in CMJ and SJ performance, and sit- ups only in SJ, were all statistically significant predictors after controlling for the effect of chronological age. Specific regression equation using calf skinfold (X1), handgrip (X2), sit-ups(X3), linear speed (35 m) (X4), and T- test (X5) to estimate the CMJ [Y = 64.69 + (-.17) (X1) + .10 (X2) + .04 (X3) + (-3.03) (X4) + (-2.32) (X5)] and SJ [Y = 64.82 + (-.32) (X1) + .09 (X2) + .05 (X3) + (-2.97) (X4) + (-2.28) (X5)] are presented. Conclusions: After controlling chronological age, calf skinfold, strength, linear speed, and agility are important predictors of explosive leg power. All these predictors should be considered in the monitoring training process to improve leg explosive power performance.