This study tested the effectiveness of Schema Therapy (ST) for borderline personality disorder (BPD) and comorbid alcohol dependence (AD). Twenty patients participated in a case series study with multiple baseline. The baseline phase consisted of treatment as usual. It was followed by a case conceptualization phase, an experiential techniques phase and a behavioral change phase. Patients showed significant decrease of BPD and AD symptoms; change was mainly accomplished in the experiential techniques phase, with medium to large effect sizes. Three months after termination of therapy, 68% of the patients had remitted from BPD, and the number of drinking days decreased clearly. This study shows that, although treatment is challenging in this group of patients, meaningful change can be obtained in patients with BPD and AD using ST.