The purpose of this study was to compare the hepatic and renal effects of modified hypotensive techniques based on sevolfurane with those based on isoflurane during middle ear surgery. The study was performed on fourty ASA I or II patients, scheduled for modified hypotensive anesthesia for middle ear surgery i.e tympanoplasty or mastoidectomy. The goal was to maintain MAP at 60 mmHg, the patients were divided randomly into two groups:Group I (ISO group) 20 patients received modified hypotensive anesthesia with isoflurane. Group II (SEVO group) 20 patients received modified hypotensive anesthesia with sevoflurane. The results of this study showed: Regarding kidney function, there were no statistically significant differences in BUN, serum creatinine, 24-h urinary creatinine and serum uric acid in both groups but, there were statistically significant postoperative glucosuria, albuminuria and proteinuria in both groups over the study period (P<0.05).Regarding liver function, there were statistically significant postoperative increase in AST ALT and total bilirubin in both groups over the study period (P<0.05) but there were no statistically significant differences in ALP, LDH in both groups over the study period.Regarding AKBR, there were no statistically significant differences between values in both groups over the study period. No statistically significant difference between ISO and SEVO groups were found in all variables over the study period.Conclusion: Modified hypotensive anesthesia using either isoflurane or sevoflurane had the same effects regarding renal and hepatic functions and specific toxicity on the kidney and the liver was not observed.