PURPOSE: This study investigated the effects that music therapy by self-selected music listening has on the affect and stress relief in adult patients who have been diagnosed with terminal cancer by pain level. METHODS: Participants were 20 terminally ill cancer patients who were over 18 years old and were admitted to the hospice and palliative care unit of a local hospital. At the beginning of each session, participants selected music of their choice. Each participant had a total of six 30-minute music listening sessions. Participants were grouped into two according to their self-rated perceived pain scores on the visual analogue scale and numeric rated score: 5 and above and less than 5. Each participant completed a questionnaire on their affect state before and after each session and a questionnaire on their stress level before the first session and after the last session. Further analysis was performed to compare differences between the two groups according to pain level. RESULTS: There were significant differences in patients' affect before and after each session (P<0.001) and stress level before and after the therapy (P=0.001). CONCLUSION: In this study, self-selected music listening had positive effects on terminal cancer patients' affect and stress regardless of perceived pain level. Therefore, self-selected music listening can be used as an appropriate intervention to improve affect and reduce stress in terminal cancer patients in the hospice and palliative care unit.