Retroperitoneal extension of perinephric abscess with fistulization to intra-abdominal and intrathoracic structures has been well documented in the literature. Intraperitoneal rupture is much less common, and exceptionally may not present as an acute abdominal condition. We describe herein 1 such case involving the spleen. Since the extent of the disease may not be apparent radiologically, and often is only ascertained at the time of surgery, we recommend an aggressive approach to renal calculi as the most effective means of preventing complicated perinephritis.