The purpose of the present study was to examine differences in ratings of perceived exertion (RPE) and the weight lifted (training load) during self-selected and imposed-intensity bouts of acute resistance exercise (RE). Nineteen untrained college-aged women completed 2 bouts of acute resistance exercise. During 1 session, 3 sets of 4 exercises were performed using a training load of 75% of 1 repetition maximum. Conversely, during the other session, each set and exercise were completed using a self-selected training load. Assessments of RPE and training load were obtained following each set during both imposed-intensity and self-selected–intensity sessions. Results of 2 (intensity) × 3 (set) repeated measures multivariate analyses of variance revealed that, when compared to self-selected RE, RPE and resistance used were significantly higher and the number of repetitions completed per set was significantly lower during imposed-intensity RE. These findings demonstrate that the training load and perceptions of effort elicited during conventional RE prescriptions differ from the level of exertion untrained women self-select. Additionally, it appears that untrained women may not self-select a relative intensity sufficient to stimulate meaningful improvements in muscular hypertrophy or strength. The implications of these findings for the adoption and maintenance of resistance exercise participation are discussed.