Intraarticular administration of morphine has good analgesic effect and satisfactory duration. It also shows less adverse effect of morphine than subarachnoid or epidural administration. However, high dose of morphine can cause long lasting respiratory depression. Although naloxone is effective in treatment of adverse effects of morphine, it has short duration of action. So repeating intravenous injections or continuous administration following bolus injection are recommended. We experienced a case of low dose continuous naloxone infusion for treatment of respiratory depression caused by iatraarticular morphine administration in total knee replacement surgery patient without affecting analgesic effect.