The development of bilateral parapelvic hemorrhagic pseudocysts with abdominal pain, systemic symptoms of malaise and fever, elevation of erythrocyte sedimentation rate and serum alkaline phosphatase, and decreased renal function is described in a patient taking anticoagulants. The symptoms and signs resolved with the resolution of the hemorrhagic pseudocysts. The bilaterality and selective localization of these hemorrhages suggest the existence of a specific pathogenesis. The advent of new imaging techniques in the last decade allows for a diagnosis and a better understanding of the pathologic processes that affect the renal sinus.