The National Drug Abuse Treatment Clinical Trials Network (CTN) is an alliance of drug abuse treatment programs and research centers testing new interventions and implementation factors for treating alcohol and drug use disorders. A workforce survey distributed to those providing direct services in 295 treatment units in the CTN obtained responses from 1750 individuals with a job title of counselor (n = 1395) or counselor supervisor (n = 355). A secondary analysis compares and describes both groups. Supervisors were more likely to be licensed or certified. Master's degrees were more common among counselors in outpatient and methadone programs. Counselors in residential settings tended to be on the job fewer years. Finally, higher education was associated with greater familiarity with and acceptance of evidence-based practices. (Contains 4 tables.)