Psychological interventions in cocaine dependent patients have demonstrated efficacy. Remarkable approaches are Contingency Management (CM) and Cognitive Behavioral Therapy (CBT). Lack of treatment adherence is the most important limitation. Motivational Interview (MI) has been shown to be an adherence enhancer. The objective of this study is to evaluate retention and abstinence in a combined CM and CBT group treatment in patients who have reached maintenance stage according to Prochaska and DiClemente's transtheoretical model (1982). Therefore, a longitudinal study was carried out with cocaine dependent patients with or without concomitant mental health disease. A 12-session open group was conducted weekly. Nineteen patients were included (78.9% men, mean age 36.6 years), 95% consumed intranasally and 47% had another psychiatric comorbidity. Treatment retention was 84%. During treatment and the first month of follow-up, all patients remained abstinent whereas at three months, 3 patients relapsed. These data confirm that using combined CM and CBT group therapy in cocaine dependents undergoing maintenance treatment enhances adherence and is effective to achieve abstinence.