This study examined time in treatment and the percentage of clients who quit or were expelled from drug treatment clinics as dependent measures in a general model including socioecological aspects of the clinic neighborhood environment, the clinic structure (attributes, e.g., size, and services and staffing), and the client composition of the clinic (sociodemographic and deviance). In this study the clinic was the unit of analysis. The data were analyzed by means of path analysis, for (1) drug free outpatient, nonopiate orientation (DFO-N) and (2) drug free outpatient, opiate orientation (DFO-O). There were 204 DFO-N and 130 DFO-O clinics. The path analytic model proved to be useful for the explanation of clinic retention outcomes. The socioecological variables predicted the types of clients who entered treatment. These in turn along with clinic attributes were significant predictors of clinic retention. Clinic attributes also predicted clinic services and staffing. The results suggested that both clinic variables and client composition variables are important predictors of clinic retention.