The present study examined whether prediction models based on the 2-km UKK Walk Test (UWT) are valid for predicting the maximal oxygen uptake or maximal aerobic power (VO2max) in moderately active Hungarian men. Eightyseven 24-62 year old, non-athletic, sedentary or moderately physically active men were studied. Maximal aerobic power was measured in a maximal uphill walk exercise test on a treadmill. The walking tests were performed on a 400-m outdoors athletic track. The subjects walked 2 km (5 laps) as briskly as they could. VO2max was predicted with the formula as established in the original development study of the UWT. The total error of prediction and the correlation coefficient between the laboratory measured and UWT predicted VO2max (ml · kg^-1 · min^-1) were 4.6 and 0.85. The Bland-Altman analysis showed a good agreement between the methods, with the mean error of prediction 0.05 ml · kg^-1 · min^-1. The results verify that the UWT can be used as a reasonably valid test for predicting maximal aerobic power in Hungarian men. © 2002 by Human Kinetics Publishers and the European College of Sport Science.