After finding that retention in methadone treatment for a year or longer was a highly significant predictor of patient outcomes following discharge, measures of pretreatment motivation and early therapeutic engagement were examined as predictors of program retention. Personal interviews were conducted with a sample of 435 patients 12 months after discharge from three methadone treatment programs. Logistic regression results showed several patient attributes--i.e. over 35, lower injection frequency before admission, and higher motivation for treatment--were each associated with twofold increases in the likelihood of having favorable follow-up outcomes on illicit drug use, alcohol use, and criminal involvement. Patients staying in treatment a year or longer, however, were nearly five times more likely to have better outcomes. Further analyses established that length of treatment stay was predicted by higher patient motivation at intake and early program involvement. The findings suggest that more comprehensive models of patient attributes, therapeutic process, and environmental influences are needed, and that treatment enhancement efforts should focus on such during-treatment measures as interim criteria for improving posttreatment outcomes.