The purpose of this study was to compare the effect of the use of music versus non-music treatment conditions in a coping skills therapy group with individuals who are dually-diagnosed with a mental illness and substance-related disorder. In order to assess the effectiveness of the music therapy procedures, a comparison was made between the non-music condition (passage selection and reflection from a book of daily readings for individuals with addiction and emotional/psychiatric illnesses) and the music condition (song choice and lyric analysis from a packet of songs created by the researcher). The participants consisted of eight individuals (M=5, F=3), dually diagnosed with a mental illness and substance-related disorder. Data was obtained through weekly surveys which assessed various factors such as level of enjoyment, accomplishment, and helpfulness in each session. The participants’ attendance, passage/song selection and the number of times they offered advice/insight to other group members was also recorded. A concurrent schedule/alternating treatments single subject experiment design was employed for this study. The participants served as their own control under two conditions: coping ability with music (song selection and lyric analysis) and coping ability with no-music (passages from a book). Participants rated both the music therapy techniques and passage selections effective, resulting in very similar scores under all of the variables except one. The extent to which the issues of chemical dependence were discussed during the sessions was rated by participants as statistically significantly higher under the music condition. During the music condition sessions, group attendance was also significantly higher than in the non-music condition sessions.