Donald Andrews and colleagues have conducted research aimed at generating principles of effective correctional treatment, i.e., treatment that can reduce rearrests and reincarcerations while helping offenders reintegrate into society (Andrews, 1995; Andrews et al., 1990). Based on this research, they argue that correctional programs should apply three principles related to risk, criminogenic needs, and responsivity. The risk principle maintains that clients who are assessed as being at higher risk for reoffending are more likely to benefit from treatment than lower risk clients; and higher risk clients should receive more intensive services than lower risk clients. According to the criminogenic-needs principle, correctional treatment should focus on needs that relate directly to criminal behavior and the risk for recidivism. The responsivity principle is concerned with the selection of styles and modes of service that are capable of influencing the specific types of intermediate targets that are set with offenders and are appropriately matched to the learning styles of offenders. Regarding reentry interventions for drug-abusing parolees, cognitive-behavioral therapy (CBT) is the most effective in reducing recidivism. CBT programs are designed to change the distorted thinking processes and patterns that foster criminal behavior. CBT programs often incorporate relapse prevention techniques. Other effective practices pertain to case management, contingency management, residential treatment, pharmacotherapy, programs for women, and continuing care. Clinical issues in treatment for parolees pertain to assessment, implementation, and mandated treatment. The article advises that these effective practices depend on collaborative systems of care that integrate the supervision and monitoring functions with treatment and service delivery. 53 references