Physiological variables must often be scaled for body size differences to permit meaningful comparisons between groups. Using multivariate allometric scaling (MAS), this study aimed to compare the anaerobic performance of adult males and females in 12 pairs matched for physical activity status. Peak power output (PPO) was assessed via a 30-s supramaximal cycle ergometer test. Fat-free mass (FFM) and thigh muscle and bone cross-sectional area (CSA) were determined anthropometrically and served as indicators of active musculature. The MAS revealed power functions of the form PPO = a.gender.FFMb (or CSAb). Common b exponents of 0.1 were identified for both FFM and CSA (negative allometry). Sex differences were found in absolute PPO (1,252 vs. 681 W, p < .05). Comparison of scaled PPO data via ANCOVA (FFM0.1 and CSA0.1 entered as covariates) did not eliminate the sex difference (adjusted means 1,243 vs. 690 W, p < .05). The results suggest that the superior anaerobic performance of males in this sample is independent of size of the involved musculature.