the purpose of this study was to determine if the level of physical training influenced the accuracy of predicting aerobic power (vo2 max) using the åstrand nomogram (1960). a total of 48 male subjects (24 trained, 24 untrained) between 19 and 36 years participated. each subject performed three åstrand nomogram tests on different days and one vo2 max test. the mean predicted vo2 max value was compared to the mean actual vo2 max value for each group. a two tailed independent t-test was used to determine if significant differences existed between the trained and untrained groups with reference to the accuracy of predicting vo2 max using the åstrand nomogram. the results demonstrated that mean differences betwen actual vo2 max and predicted vo2 max were significantly different (t(46)=2.61, p<.05) for the trained and untrained group. comparison of the predicted vo2 max (age corrected) to the actual vo2 max produced a correlation of .79 (p<.05) for the untrained group and .60 (p<.05) for the trained group. the per cent error was 10.5% and 15% for the untrained and trained group, respectively. it was concluded that the level of physical training did influence the accuracy of predicting vo2 max using the åstrand nomogram. when a correction factor based on actual maximum heart rate was used for the trained subjects, the åstrand nomogram became a better predictor of vo2 max for the trained subjects.