This study examines the effect of homework compliance on treatment outcome in 123 participants receiving cognitive-behavioral therapy (CBT) for cocaine dependence. Regression analyses revealed a significant relationship between homework compliance and cocaine use that was moderated by readiness to change. Homework compliance predicted less cocaine use during treatment but only for participants higher in readiness to change. For those lower in readiness to change, homework compliance was not associated with cocaine use during treatment. Homework compliance early in therapy was associated with better retention in treatment. Homework compliance was not predicted by participants' level of education or readiness to change. These findings support the use of homework during CBT for substance use disorders.