Effective postincarceration treatment for individuals with preincarceration heroin dependence is urgently needed because relapse typically follows release. This article presents first-year findings from a unique 2-year pilot study of opioid agonist maintenance treatment initiated in prison and continued in the community. Incarcerated males with preincarceration heroin dependence were randomly assigned to Levo-alpha-acetylmethadol (LAAM) maintenance or control conditions 3 months before release. Approximately 92% of eligible inmates volunteered to participate; 36 of 58 subjects who were eligible and randomly assigned to LAAM maintenance successfully initiated treatment. Twenty-eight of these continued on LAAM until release; 22 (78.6%) entered community-based maintenance treatment; and 11 (50%) remained in treatment at least 6 months postrelease. Changes in LAAM's labeling because of its association with cardiac arrhythmias now makes it a second-line treatment for heroin dependence, unsuitable for treatment initiation. Nonetheless, study findings may also be applicable to methadone maintenance treatment, suggesting such treatment may be a promising means of engaging prisoners with preincarceration heroin dependence into continuing treatment.