Background: Stigma surrounding substance use disorder (SUD) is highly prevalent in health care. Negative attitudes toward patients with SUD have been shown to negatively impact patient care. Addressing SUD stigma in medical students is a promising approach, however, few curricula include experiential learning on addiction psychiatry clinical services. We describe a medical student rotation on an addiction psychiatry clinical service and examine its effect on attitudes toward patients with SUD. Methods: Medical students were integrated onto an addiction psychiatry consultation-liaison service serving medically/surgically hospitalized patients with co-occurring SUD and other psychiatric disorders. Students learned and practiced in-person assessment of patients and received instruction on basic principles of psychiatry and evaluation and management of SUD. A targeted anti-stigma curriculum was included. Attitudes toward patients with SUD were measured with the Medical Condition Regard Scale (MCRS) before and after the experience. Each item of the MCRS and an overall composite attitude score were analyzed. Results: Of the 36 students on the clinical rotation, 33 completed the survey. Attitudes showed widespread improvement toward patients with SUD. Mann–Whitney U tests showed significant improvement in most items of the MCRS. Further analysis of composite scores showed an improvement in overall attitudes toward patients with SUD. Conclusions: Inclusion of medical students on an addiction psychiatry consult service as part of the core psychiatry clerkship may hold promise for helping improve student attitudes and decrease stigma toward patients with SUD. Controlled study is needed to compare other clinical experiences and determine specific causative effects.