Acute renal failure after biliary tract surgery was first described by Clair-mont and VonHaberer {1911}. The cause of supression of renal function in patients with obstructive jaundice is controversial. Dawson (1964) sug­gested deficient renal perfusion. He reported significant improvement of kindey function following mannitol diu­resis. Endotoxaemia has a deleterious effect on renal function and structure. Endotoxaemia is due to absence of bile salts from the small itestine (Cavanough et at. 1970) and Mckay et al. (1966). After biliary drainage (PTD), Lygid-akis (1987) showed improvement of blood urea, serum creatinine and creattnine clearance. Thompson et ai., (1986) using isotopic renal scan DTPA showed that in jaun- diced patients G. F. R. was lower be­fore biliary drainage than controls and that it increased significantly after drainage. In this paper we studied renal func­tion in 15 patients with obstructive jaundice before and after biliary drain­age using isotopic renal scan in one surgical unit in Mansoura teaching hospital.