Workup of a woman presenting with a palpable right flank mass, detected bilateral renal solid lesions, later proved to be renal cell carcinomas, and caval invasion in the presence of duplicated inferior vena cava. This association does not appear to have been previously described. The patient underwent right radical nephrectomy, cavotomy and auriculotomy with caval thrombus removal and delayed enucleation of left renal masses and left adrenalectomy. Eighteen months after surgery the patient is alive and without local and distant recurrence.