This study identifies factors that predict daily cocaine use among clients in a methadone maintenance program who participated in a cocaine treatment trial. Cocaine use decreased the longer clients remained in treatment, and the amount of cocaine used depended upon the day of the week, with Saturday typically having the greatest use and Sunday having the least. Logistic regression analyses showed that several other factors were related to daily cocaine use: peak cocaine craving, resistance to use cocaine, and several triggers or stimuli to use cocaine. These stimuli included receiving money, being offered cocaine, and seeing cocaine and/or related paraphernalia. However, even with these variables controlled, day of the week and time in treatment continued to be significant predictors. This suggests that (a) other time-varying variables need to be included in order to fully account for cocaine use variation from day to day and (b) time in treatment is a robust predictor of reduced cocaine use despite the strong influences of craving, external stimuli, and day of the week.