To determine ratings of perceived exertion (RPE) at the anaerobic threshold (AT), 13 men and 17 women, 21 to 37 years of age. performed a progressive, load-incremented bicycle ergometer stress test during which physiological measurements and RPE were obtained every 30s. The mean (± SD) AT expressed as a percentage of the maximal oxygen uptake was 60.1 ± 7.8 and 60.3 ± 7.7 for males and females respectively. Ratings of perceived exertion at anaerobic threshold (RPE-AT) ranged from 11 to 16. The mean RPE-AT for females (13.1 ±0.9), males (14.2± 0.9) and the combined group (13.6+1.2) corresponded to a perception of work as ‘somewhat hard’. It was concluded that young men and women perceive an exercise intensity equal to the anaerobic threshold as ‘somewhat hard’. The similar perception of the exercise intensity corresponding to anaerobic threshold by different individuals makes it possible to prescribe an exercise intensity equivalent to the anaerobic threshold using ratings of perceived exertion.