Xanthogranulomatous Pyelonephritis ( XGN) is a rare form of chronic pyelonephritis which is characterized by focal or diffuse destruction of the renal parenchyma and replacement by solid sheets of lipid–laden macrophages ( xanthoma cells). It was first described in 1916 by Schlagenhaufer. It can be seen in all age groups, but most commonly seen in middle–aged to elderly patients (45–65 years) . More commonly seen in females with 4:1 female: male predilection, mostly related to an increased incidence of urinary tract infections and thus struvite (staghorn) calculi. Increased incidence is also seen in patients with diabetes mellitus. In the past, the preoperative diagnosis was extremely difficult due to its nonspecific clinical presentation and radiographic appearances. Now a days, the ability to diagnose it preoperatively has considerably improved with the use of ultrasound and computed tomography . Clinical presentation is non specific, consisting of constitutional symptoms such as anorexia, weight loss ,malaise, and low–grade fever. Haematuria and flank pain can also be present. CT scan is investigation of choice for its diagnosis.