Background: Music therapy can positively impact craving, treatment readiness, and motivation in adults with substance use disorder (SUD) on a detoxification unit. However, the existing research is primarily comprised of studies with a single pre- or posttest and there is a need for randomized controlled studies that compare within-session changes resultant of various music therapy interventions to determine best practice. Objective: The purpose of this single-session study was to compare within-session changes between group motivational and educational songwriting (MESW) and group recreational music therapy (RMT) on craving and commitment to sobriety in adults with SUD on a detoxification unit. Method: Participants (N = 100) were cluster-randomized to group MESW or group RMT conditions and completed established psychometric instruments measuring craving and commitment to sobriety at pre- and posttest. Results: Within-group changes were significant in all measures, indicating that music therapy was effective within the temporal parameters of a single session. Although between-group differences were not significant, mean within-session improvements in expectancy, compulsivity, emotionality, total craving, and commitment to sobriety were larger in the MESW condition than the RMT condition. Additionally, the MESW group tended to have slightly more favorable posttest scores than the RMT group in all measures. Conclusion: Despite the temporal limitations of single-session therapy common on detoxification units, both MESW and RMT protocols resulted in significant within-session changes in measures of craving and commitment to sobriety. Implications for clinical practice, limitations of the study, and suggestions for future research are provided.