Volunteers for the project were recruited from individuals entering the Jefferson Outpatient Cocaine Treatment Clinic in Philadelphia who met the following criteria: first admission, above 18 years of age, and DSM-III-R diagnosis of cocaine dependence. In addition, patients were selected who were not overtly psychotic, actively suicidal, or cognitively impaired to the extent of not being able to participate in the project. Initial and follow-up assessments revealed pretreatment dropouts were more often positive for cocaine on admission drug screens and less often employed. They reported fewer psychological symptoms on scales of the Symptom Checklist and received lower scores on the medical problem severity scale of the Addiction Severity Index. At 9-month follow-up, they were found to have less often attended self-help meetings or continued in outpatient treatment, more often to have been admitted for inpatient treatment or been in jail, less often returned to school, and more often used cocaine. The authors conclude clinicians and researchers need a better understanding of patients who account for significant attrition in drug treatment programs, have distinguishing characteristics, and do much more poorly than those who remain in treatment. 24 references and 2 tables