The following study, conducted in Puerto Rico, examined the feasibility of providing daily buprenorphine-naloxone (bup-nx) in prison and on release to 45 male inmates with histories of heroin addiction. Participants were assessed at study entry and at 1 month after release (N = 42; 93.3% follow-up rate). Treatment completers compared with noncompleters had significantly greater reductions in self-reported heroin use, cocaine use, and crime and were less likely to be opioid-positive according to urine drug testing. Despite study limitations, the short-term outcomes of this study suggest that bup-nx may contribute to reductions in readdiction to heroin and in criminal activities among re-entering male prisoners.