Despite its potential for determining animal success in a variety of ecologically important situations, very little is known about the sprint swimming performance of fishes. To evaluate whether selection on sprint swimming performance occurs in the wild, one must first demonstrate measurable and reproducible variation of sprint performance. In this study, we employ a computer-controlled laser detection system to study the sprint performance of 75 juvenile European sea bass Dicentrarchus labrax raised under uniform conditions in the laboratory. This percichthyid is a prized sport and food fish in Europe and similar ecologically to the North American striped bass Morone saxatilis. Individual European sea bass were subjected to endurance swimming performance tests and had their active metabolic rates measured to test hypotheses concerning relationships between these measures and sprint performance. Maximal velocity obtained by an individual during repetitive sprint performance trials was very reproducible but varied substantially among individuals. Consecutive sprint trials with an individual revealed that maximal capacity for sprinting could only be ascertained through multiple trials (at least four). The sprint performance test described in this study should be useful for large-scale studies in which investigators desire performance information on a large number of animals relatively quickly. However, active metabolic rate measurements and an endurance test were not considered effective performance measures for juvenile European sea bass, and there was no relationship between sprint swimming performance and either of the tests.