The effect of a 12-week high-intensity intermittent exercise (HIIE) intervention on the rating of perceived exertion (RPE) response of young males was examined. Participants (N = 38; M BMI = 28.7 kg x m(-2), SD = 3.1; M age = 24.9 yr., SD = 4.3) were randomly assigned to either an exercise or control group. The exercise group received HIIE three times per week, 20 min. per session, for 12 weeks. RPE was assessed before and after HIIE training and during pre- and post-maximal oxygen uptake (VO2 max) testing. After HIIE training, RPE was significantly higher in Weeks 11-12 compared to Weeks 1-2. In contrast, heart rate was similar throughout training. Comparing post- to pre-VO2 max test, RPE was significantly lower in the exercise group, whereas for controls, RPE was similar. Aerobic power improved 15% for the exercise group, with no significant change for controls. HIIE resulted in significant increases in RPE, whereas RPE during the VO2 max test was significantly decreased.