Acute renal failure due to paradoxical embolism is exceptionally reported. A new case gives the opportunity to review mechanisms, diagnosis and therapeutic issues. A 49-year-old woman without medical history is admitted for crural venous thrombosis and acute pulmonary embolism. At day 2, a left flank acute pain with fever, doubling of plasma creatinine, and controlateral recurrence at day 12, leads to diagnosis of acute bilateral renal infarction only at day 20. Paradoxical embolism is then suspected and confirmed by transoesophageal contrast echocardiography, disclosing patent foramen ovale with right-to-left shunt. Nine months later, successful percutaneous closure of patent foramen ovale with Amplatzer PFO occluder 25 mm allows subsequent discontinuation of oral anticoagulation. Diagnostic criteria for paradoxical embolism are present in our case. If this mechanism is often discussed in cryptogenic cerebrovascular stroke of young patients, it is exceptionally reported as responsible for clinical renal disease, particularly acute renal failure (whereas anatomical renal involvement is not unfrequent). The clue is the difficulty to suspect and confirm renal infarction, especially when classical causes of cardiac embolism are lacking. The relevance is the opportunity to save renal tissue in the acute phase, and to close patent foramen ovale (currently most often percutaneously) weeks or months after the acute bout.