A case of perinephric xanthogranulomatous pyelonephritis is presented. Ultrasonography and X-ray computed tomography (X-CT) showed a mass on the posterior aspect of the right kidney, causing us to suspect right renal cell carcinoma. Pyelography showed a deformity of the right renal calyces. From angiographic results, we considered the possibility of hypovascular renal cell carcinoma, subcapsular tumor, or retroperitoneal tumor. The mass was diagnosed pathologically as perinephric xanthogranulomatous pyelonephritis.