Xanthogranulomatous pyelonephritis is a chronic inflammatory condition which in most cases involves either an entire non-duplicated kidney or a moiety of a duplicated kidney. These cases present with quite characteristic radiologic findings including an enlarged non functioning kidney and renal stones. However, when the condition involves only a part of a non-duplicated kidney and especially where there is an absence of the specific findings described above, differentiation from cystic neoplasm may be difficult. We report the radiologic findings of twosuch cases of focal xanthogranulomatous pyelonephritis.