This study was designed to examine the accuracy of air-displacement plethysmography (ADP) using Lohmans age-adjusted equations (Leq) and Siris equation (Seq) in estimating body fat (BF) in male adolescent athletes, with the four-compartment (4C) model as reference. Subjects were 51 Caucasian boys (age, 15.51.2 years; weight, 71.011.9 kg; stature, 1.790.12 m). Comparison of means with the Wilcoxon test showed that BF estimates with Seq to be different from those with Leq and 4C model, (8.84.4 vs. 7.94.5 and 8.14.0 kg, respectively) (p0.001), suggesting an overestimation of BF. However, BF estimates with the Leq and with the 4C model were identical (p0.05). Estimates using Seq and Leq with the 4C model were similar, as shown by the 95% confidence intervals (-4.72.4 and -4.03.7, respectively). These findings suggest that in male adolescent athletes, the use of Leq improves estimates of BF by densitometry using ADP.