ABSTRACTDespite the widespread use of psychotherapy as treatment for cocaine abuse, the effectiveness of psychotherapy has not been explored through clinical trials. Forty-two outpatients who met DSM-III criteria for cocaine abuse were randomly assigned to one of two forms of purely psychotherapeutic treatments of cocain abuse, either relapse prevention (RPT) or interpersonal psychotherapy (IPT). Subjects assigned to relapse prevention were more likely than subjects in IPT to attain three or more continuous weeks of abstinence (57 versus 33%), be classified as recovered at the point of treatment termination (43 versus 19%), and complete treatment (67 versus 38%). Whereas these differences did not reach statistical significance, significant differences by treatment group did emerge when subjects were stratified by severity of substance use: Among the subgroup of more severe users, subjects who received RPT were significantly more likely to achieve abstinence (54 versus 9%) and be classified as recovered (54 versus 0%). Among the subgroups of subjects with lower severity of substance abuse, outcome was comparable for both treatment types. Comparison of results from this investigation with historical controls from a structurally similar pharmacotherapy trial suggests that purely psychotherapeutic treatments may be both viable and effective approaches for many ambulatory cocaine abusers.