Myoglobinuric acute renal failure (mARF) is an uremic syndrome which develops due to damage of skeletal muscle. It was demonstrated that free radicals and nitric oxide (NO) play an important role in pathogenesis of mARF. Our aim was to investigate the effect of losartan, a drug known for its antioxidant effect, on mARF. In our study, a total of 34 male Spraque Dawley rats were divided into four groups. 1st and 2nd groups were injected with saline, 3rd and 4th groups were injected with intramuscular glycerol. One and 24 hours later, 1st and 3rd groups received saline orally and 2nd and 4th groups have taken 10 mg/kg losartan. Urine was collected; the blood samples and kidneys of the rats were taken under the anesthesia. The levels of NO, arginine, asymmetric dimethylarginine (ADMA), glutathione (GSH) and malondialdehyde (MDA) were determined, renal functions and histopathological changes examined. In our study, we found that levels of urea, creatinine, and potassium, in serum samples and MDA and ADMA in renal tissue were increased in 3rd group when it's compared with the 1st group. Levels of sodium, arginine in serum samples and arginine in renal tissue were reduced 3rd group when compared with the 1st group. When 3rd and 4th groups were compared, serum creatinine was higher in the latter group whereas ADMA level in renal tissue was lower in the same group. We think that there is no positive effect of losartan on the pathogenesis of mARF.