The movement patterns and heart rate responses of Soccer referees during matches were examined. A movement analysis was performed using a grid method and subjects wore a PE 3000 heart rate monitor during the match. The mean distance (+/- SD) covered was 9,408 m (+/- 838m) which comprised: walking (18.9%), jogging (46.6%), running/striding (12.1%), sprinting (6.2%) and backwards movement (16.2%). If walking and jogging are pooled as low intensity activity and high intensity work is defined as running/striding and sprinting then the majority of distance was covered by low intensity activity (65.5%). No differences in the total distance covered during the two halves was evident. However, in the second half the subjects walked more than in the first half (p < 0.01), while they ran/strode more in the first when compared to the second half (p < 0.01). The subjects' mean heart rate during the first and second halves was not significantly different and were 163 and 162 beats per minute (b.min-1) respectively. If the theoretical maximum heart rate for each subject (220-age) is used, the major percentage of the time was spent at heart rates above 85% HRmax. Based upon the distance results of this study, the major energy source for Soccer refereeing would appear to be the aerobic system with the anaerobic system contributing to ATP production to a lesser extent. The results of this study suggest that refereeing at a high level places a significant physiological demand upon these athletes; they therefore require specialised assessment and training.