This study examined the ability of 40 children (20 boys and 20 girls), ages 11 to 14 years, to regulate the intensity of their effort using perceived effort ratings during cycling. The Borg Rating of Perceived Exertion 6 to 20 Scale was learned and used as a perceptual frame of reference. Maximal oxygen uptake and power output were predicted from telemetered heart rate data collected during a submaximal graded exercise test. Subjects were then fully familiarized with the RPE scale and attended three consecutive sessions of cycling during which they adjusted the workloads themselves so as to produce effort intensities for scale ratings of 9 (very light), 13 (somewhat hard), and 17 (very hard). Heart rates were sampled during the final half minute of each session and the data were submitted to a mixed factorial analysis of variance. This showed highly significant differences (p<.001) between the three RPE levels but no significant effects for age, gender, or trials. It was concluded that the RPE is readily learned by older children and adolescents and is a potentially useful frame of reference when self-regulating effort intensity during vigorous exercise.