This study aimed to investigate the effect of music on pain, anxiety, comfort, and functional capacity of cancer patients who received care in a palliative care unit. The population of this randomized controlled trial consisted of cancer patients hospitalized in the palliative care service between July 2018 and July 2019. The study included 60 patients (30 interventions/30 controls). The patients in the intervention group were given a total of six music sessions, 10 minutes each with the Turkish classical music in maqams of their choice (Hejaz or Rast accompanied by an expert tambour (drum) player). There was a significant difference between the mean total pain scores, anxiety, comfort, and functional capacity scores of the patients in the intervention and control groups before and after music therapy. Music therapy decreased the level of pain. It is demonstrated that Turkish classical music therapy improved the pain, anxiety, comfort, and functional capacity in the palliative care unit.