This study was aimed to evaluate renal dysfunction during three weeks after the burn injuries in 12 patients admitted to the Hallym University Hankang Medical Center with flame burn injuries (total body surface area, 20-40%). Parameters assessed included 24-hr urine volume, blood urea nitrogen, serum creatinine, creatinine clearance, total urinary protein, urinary microalbumin, 24-hr urinary N-acetyl-β-D-glucosaminidase (NAG) activity, and urinary malondialdehyde (MDA). Statistical analysis was performed using repeated measures ANOVA test. The 24-hr urine volume, creatinine clearance, and urinary protein significantly increased on day 3 post-burn and fell thereafter. The urine microalbumin excretion showed two peak levels on day 0 post-burn and day 3. The 24-hr urinary NAG activity significantly increased to its maximal level on day 7 post-burn and gradually fell thereafter. The urinary MDA progressively increased during 3 weeks after the burn injury. Despite recovery of general renal function through an intensive care of burn injury, renal tubular damage and lipid peroxidation of the renal tissue suggested to persist during three weeks after the burn. Therefore, a close monitoring and intensive management of renal dysfunction is necessary to prevent burn-induced acute renal failure as well as to lower mortality in patients with major burns.