The study was conducted at the California Substance Abuse Treatment Facility (SATF) and State Prison at Corcoran, CA. The SATF treatment program involves a 6- to 18-month in-prison phase followed by a voluntary community treatment phase. Criteria for assignment to the program include a history of drug and/or alcohol abuse; no placement in a secured housing unit during the past year for violence or weapons charges; not a member of a prison gang; and no active or potential felony or U.S. Immigration and Naturalization Service holds. Similar percentages of voluntary and involuntary admissions were paroled from treatment (as opposed to being discharged from the program prior to parole) and agreed to attend community treatment. Voluntary and involuntary admissions to the program exhibited equivalent outcomes, but the study emphasized that coercion per se did not lead to successful treatment. To maintain their level of success and to minimize disruption in their treatment sessions, treatment providers are advised to modify their program to take into account the high resistance levels of many coerced clients. Tables, references