This study assessed the effects of music with bone marrow transplant patients on exercise endurance, motivation, psychological well-being, and physical comfort. Exercise, although difficult due to treatment effects, is necessary to reduce or prevent muscle atrophy. The subjects were 3 females and 3 males ranging in age from 14 to 53 years. Two subjects received 10 sessions, while 4 others were seen between two to three sessions each. A music/nonmusic reversal design ABABAB (etc.) was used. independent variables included live and recorded music for patiicipation, relaxation and imagery, progressive relaxation exercises, range of motion exercises, and aerobic exercise. The dependent variables included an observational behavior scale, subject self-report of relaxation, comfort, pain and nausea levels, exercise endurance, and an end-of-study effectiveness questionnaire. Long term results (10 sessions) indicated that music sessions were most effective in increasing subjects' self-report relaxation and comfort levels. Endurance for both subjects increased during sessions with music. More cooperafive behavior and higher participation levels were also observed during music sessions. Short term results (two to three sessions) indicated that music sessions were more effective in increasing relaxation and comfort levels. No short term subjects showed an increase in endurance during music versus nonmusic sessions.