OBJECTIVE To identify and relate body fat percentage (skin fold measures), body mass index (BMI) and age at menarcheto aerobic capacity using the indirect VO₂ maximum value (VO₂ max) of girls in the second cycle of primary school. METHODS A total of 197 girls aged 13.0 ± 1.2 years on average, students from two public schools in the city of Atibaia in São Paulo, were evaluated. Anthropometric evaluation of skin folds was performed using the Slaughter protocol for teenage girls, and BMI (kg/m²) was based on "Z score" (graphic of percentile) according to WHO recommendations. The Léger protocol was used to determine VO₂ max. Pearson linear regression and the Student t-test were used for statistical analysis. RESULTS 22.3% of the girls were overweight and 3.5% were obese according to the classification proposed by the WHO; 140 (71.1%) girls reported menarche. The average age at menarche was 12.0 ± 1.0 years and was significantly higher in the group with normal BMI (12.2 ± 0.9 years) than in the overweight or obese groups (11.6 ± 1.0 years). The average indirect VO₂ max value was 39.6 ± 3.7 mL/kg/min, ranging from 30.3 to 50.5 mL/kg/min. The advance of chronological age and early age at menarche were positively correlated with lower VO₂ max values. CONCLUSIONS This study showed that 25.8% of the girls had aBMI value above WHO recommendations. Girls with higher BMI and higher body fat percentage had lower VO₂ max. The earlier age at menarche and the advance of chronological age were the most important factors for the reduction of aerobic capacity. The ageat menarche was higher in girls with adequate BMI compared tooverweight or obese girls.