The aim of this study was to compare temperamental profiles of patients who completed inpatient treatment of drug dependence with those who failed to complete the program. One hundred forty four opiate addicts, all resident in therapeutic communities and screened to exclude Axis I disorders, were assessed using the Temperament and Character Inventory (TCI). After one year, the TCI scores were compared between those who were still resident and those who had dropped out. Significant differences between groups were found in Reward Dependence, Persistence, Cooperativeness, Self-Transcendence. Temperament and character features may have an influence on motivation and on the adherence to treatment and community rules, as they modulate the maintenance of ongoing behaviors and the sensitivity to social rewards. The findings suggest that personality assessment with TCI in opiate addicts may be helpful in screening procedures to increase the efficiency of treatment and rehabilitative strategies.