BACKGROUND: In inducing anesthesia for burn patients, nondepolarizing muscle relaxant (NDMR) is usually used, because succinylcholine, a widely used muscle relaxant may cause hyperkalemia. It is well known that because burn patients show resistance to NDMR, a high dose of NDMR is needed for them. In this study, we wanted to know whether there is significant difference of the relaxation effect between 0.1 mg/Kg and 0.15 mg/Kg dose's of vecuronium, and between burn and unburn patients. METHODS: Subjects are 40 male patients having 1 or 2 ASA physical status (20 are burn patients and the other 20 are unburn patients). We divided them into 4 groups; 1) Group BI (burn patients, vecuronium 0.1 mg/Kg) 2) Group BII (burn Pts, vecuronium 0.15 mg/Kg) 3) Group UBI (unburn Pts, vecuronium 0.1 mg/Kg) 4) Group UBII (unburn Pts, vecuronium 0.15 mg/Kg). Average onset times (time from injection of vecuronium to zero first twitch height (T1)) were measured and intubating condition were scored on 0 to 4 scale. RESULTS: The onset time of vecuronium and distribution of intubation scores didn't show statistical differences among 4 groups. CONCLUSION: The onset time of vecuronium and intubating condition in burn patients dosen't show a difference from unburn patient.