Sickle cell disease (SCD) pain remains difficult to manage. This pilot study evaluated single-session biofeedback-assisted relaxation training (BART) for SCD pain in children. Ten participants (mean = 12.1 y) completed a 1-hour BART session using thermal biofeedback and home practice. Participants demonstrated changes in peripheral body temperature after the training session (d = 1.08) and at 6-week follow-up (d = 0.97) relative to their baseline visit. Reductions in patient-reported pain frequency were found after completing BART. Health-related quality of life and pain-related disability improvements were observed; however, effect sizes were small to minimal. Single-session BART may be a promising, complementary approach to medical management of pediatric SCD pain.