The purpose of this study was to determine whether maximally accumulated oxygen deficit (OD) was a valid index of anaerobic capacity by distinguishing among groups of aerobically and anaerobically trained athletes. In addition, OD was correlated with commonly used anaerobic capacity/power measures. Subjects were four distance and five middle distance runners, three sprinters, and four controls. Subjects performed one 2-3 minute supra-maximal treadmill run in which blood lactates were recorded, a Wingate Bicycle Ergometer Test, and runs of 300, 400, and 600 meters. Data were analyzed by ANOVA and a Duncan's Multiple Range test. Significant differences in OD were found between: sprinters and middle distance runners vs. distance runners and controls suggesting a greater anaerobic capacity in the former two groups. Significant correlations also were found between OD and the other anaerobic tests. This study demonstrates that OD can distinguish among groups of track athletes whose events require varying levels of anaerobic metabolism. Correlations between OD and selected field tests suggest that the latter are measuring some common aspects of anaerobic ability.