Alternate-day buprenorphine dosing was compared to daily dosing in opioid-dependent outpatients and choice of alternate-day versus daily dosing was assessed. Four dosing schedules were presented in random order under blind and open dosing conditions. Subjects received two exposures to each dosing schedule. During daily dosing, subjects received maintenance doses every 24 h. During blind alternate-day dosing, subjects received double maintenance doses every 48 h; placebo was interposed on intervening days. During open alternate-day dosing, subjects received twice their maintenance dose on Monday, Wednesday and Friday and maintenance doses on Sunday. After completing two exposures to each dosing schedule, subjects chose either daily or alternate-day schedules each week for 1 month. Study participation was contingent on daily attendance and opioid abstinence. Ten subjects were exposed to the four conditions once. Seven subjects repeated these conditions and participated in the choice phase. The effects of daily versus alternate-day dosing were not influenced by blind or open dosing conditions. Subjects' ratings of withdrawal, "sick" and sedation were lower during daily than during alternate-day dosing, but the difference between treatments was small. Nonetheless, subjects still chose alternate-day dosing on 96% of occasions, suggesting that the subject-rated differences between dosing schedules were not influential. These results extend prior findings to open-dosing conditions, and replicate the safety and acceptability of alternate-day buprenorphine treatment. Choice of alternate-day buprenorphine administration underscores the procedure's clinical utility and potential use as a positive reinforcer to enhance opioid treatment.