The purpose of this study was to examine the role of upper body anaerobic power, as measured by the Wingate Anaerobic Arm Test (WAAT), in 50-m sprint swim performance. Thirty competitive age-group swimmers (14 males and 16 females) participated in this investigation. Subjects had been training daily for 5 months prior to the study, swimming an average of 6,000 m.d-1, 6 d.wk-1. Swimmers performed a WAAT and a 50-m time-trial. Peak power (PP), mean power (MP) and fatigue index (FI) were determined for the WAAT. Subjects also reported their current competition performances for all distances up to 400 m. Significant relationships were obtained between swim speed over 50 m (S50) and PP (r = 0.82, p less than 0.001), S50 and MP (r = 0.83, p less than 0.001), and S50 and FI (r = 0.41, p less than 0.05). PP and MP showed significant but generally decreasing correlations with swim speed as distance increased. Substantial relationships (r = 0.74-0.96, p less than 0.001) were found between S50 and swim speeds over distances up to and including 400 m. This study shows a strong relationship exists between upper body anaerobic power, as measured by the WAAT, and performance in both sprint and longer distance (400 m) swim events. The WAAT may serve as a useful tool for coaches to objectively evaluate and monitor the upper body anaerobic power of competitive swimmers.