Exercise prescription guidelines for breast cancer patients have yet to be established. The purpose of this study was to compare the heart rate (HR), rate of perceived exertion (RPE), and post-exercise blood lactate responses to aerobic exercise between post-treated breast cancer patients and apparently healthy controls. Fourteen subjects (7 patients, 7 controls) participated in this study. Three different exercise intensities (40%, 60%, and 70% of VO2max) were examined. No differences were observed in HR, RPE, or post-exercise lactate for the exercise trials, with the exception of lactate after the exercise trial at 70% of VO2max, where the control group had a significantly higher response compared to the experimental group (p<0.0005). Post-treated breast cancer patients seem to respond similarly to these 3 exercise intensities compared with apparently healthy controls. However, methodological challenges faced during this study should be addressed for a more clear understanding of the current findings.