The purpose of this study is to evaluate the effectiveness of buspirone in attenuating withdrawal symptoms in heroin addicts and methadone-maintained patients following cessation of heroin or methadone use. Subjects were twenty hospitalized male chronic opiate users aged 30-55 who did not present any DSM-IV Axis I disorder with the exception of opioid dependence. For the first five days, patients received doses of methadone that were decreased to 30 mg and were maintained on this dose for the following three days. Methadone was then discontinued, and patients were randomly assigned to buspirone or placebo treatment from day nine to seventeen. The buspirone dose was 15 mg on day nine and 30 mg from day ten to day seventeen. Treatment was double-blind. Withdrawal symptoms were measured with the Objective Opiate Withdrawal Scale (OOWS) and the Subjective Opiate Withdrawal Scale (SOWS). Buspirone-treated patients had significantly lower scores on the OOWS on days thirteen (p=.040), fourteen (p=.025), fifteen (p=.035), and seventeen (p=.035). They also had lower scores on the SOWS on days sixteen (p=.050). It is concluded that buspirone was effective in attenuating the objective and subjective withdrawal symptoms that follow opiate use cessation.