 Background. Though buprenorphine effectively treats opioid dependence, some abstinent patients relapse to maladaptive use of opioids during treatment. Relapse may be triggered by stress. Rodent studies have demonstrated that stress can induce relapse to heroin and cocaine use Erb, et al., 1996; Shaham, et al., 1996; Shaham and Stewart, 1995. In a rodent model, stress-induced relapse to heroin and cocaine seeking is blocked by the alpha-2 adrenergic agonist clonidine. In this study, clonidine will be compared to placebo in preventing relapse to opioid abuse in opioid maintained patients who have achieved abstinence while on buprenorphine and contingency management. 