This study was undertaken to determine which of the two commonly used field tests, the 20-meter shuttle run test (20-MST) or the University of Montreal track test (UM-TT), provides the most accurate assessment of maximal and functional aerobic capacity in moderately trained athletes. Eleven male subjects aged from 18 to 30 years were studied in triple incremental and continuous running tests carried out until exhaustion both in laboratory and field conditions. They underwent a laboratory treadmill test and completed the outdoor 20-MST and UM-TT. During the three randomly assigned tests, maximal velocity (Vmax), maximal oxygen uptake (VO2max), maximal heart rate (HRmax), and post-exercise peak blood lactate (P[La]) measurements were made. The results indicate a significant difference in the mean Vmax (F = 9.26, p less than 0.001). Vmax determined by the 20-MST revealed a lower value than by treadmill (16.3%) and the UM-TT (19.3%). In contrast, there was no difference with regard to VO2max (F = 2.95, p = 0.06), HRmax (F = 2.72, p = 0.08), and P[La] (F = 2.79, p = 0.07). These results confirm that the UM-TT is a valid field test of maximal and functional aerobic capacity in moderately trained subjects and suggest that it can be additionally used for exercise prescription.