Aim: Thermal injury elicits several systemic consequences. Acute renal failure (ARF) is a well known complication of severe burn and is an important factor leading to an increase in mortality. We aimed to focus on early diagnosis of acute renal failure occurring in major burns and to determine the predictors for acute renal failure. Methods: Forty patients with moderate to severe thermal burn injury - second to third degree with >20% of total body surface area - constituted the material of our study. The following parameters were recorded: Age, sex, cause of the burn injury, burn surface of second and third degrees expressed as total body surface area burned in %, Apache II score. All patients were subjected to routine investigations including: Serum creatinine, blood urea nitrogen, fractional excretion of sodium, urinary malondialdehyde and microalbuminuria were done on day 0, 3, 7, 14 and 21. Results: Nine patients (22.5 % of all cases) - developed acute renal failure, 4 patients required supportive dialysis. The group that developed ARF showed rising of markers of glomerular damage with appearance of microalbuminuria on day 0, that was maximal (3 - 4 folds of its normal level ) at day 14 and constant with elevated serum creatinine and burn size in the 3rd week and progressed to overt proteinuria in 3 cases. Urinary malondialdehyde was also elevated before developing acute renal failure about 3 folds their normal values, gradually increasing on day 14 associated with rising of microalbuminuria followed by their decrease after controlling of septicemia. Two cases (22.2%) in ARF group who developed septicemia and required dialysis died on the 32nd and 36th days post-burn. Burn size and occurrence of septicemia were the only predictors of acute renal failure using multiple regression analysis, (SE B 0.003 and 0.104- P value 0.001 and .0371 respectively). Conclusion: Acute renal failure complicates 22.5 % of burn patients that was found to be related to the size and depth of burn. Microalbuminuria and urinary malondialdehyde are useful markers for prediction of renal outcome in such group of patients. In our study burn size and septicemia proved to be the only clinical parameters that predict renal outcome.