Vecuronium, a nondepolarizing neuromuscular blocking agent, has been used in patients with severe respiratory failure to reduce oxygen consumption and improve total thoracic compliance (1, 2). For short-term administration, vecuronium is regarded as a medication producing therapeutic benefits with few side-effects (3–5). However, the long-term use of vecuronium (>3 days) has been the topic of only two published reports (6, 7).In our ICU, patients initially receive a loading dose of 0.1 mg/kg vecuronium followed by a maintenance infusion of 0.07 to 0.14 mg/kg-hr (8). Some patients exhibit a “resistance” to the agent and require considerably greater hourly doses to permit controlled mechanical ventilation. Nerve stimulators may not be of value to assess degree of paralysis, since the ulnar nerve response to Train-of-Four method does not accurately represent the degree of diaphragmatic paralysis (9). Despite higher than recommended doses and lack of monitoring, most patients regain neuromuscular function within 24 to 48 hrs. Occasionally, however, a patient remains paralyzed for weeks.We describe a patient with severe adult respiratory distress syndrome without renal or hepatic dysfunction, who manifested prolonged paralysis after longterm use of a continuous vecuronium infusion.