A patient is described in whom a caliceal fistula occurred after renal transplantation due to secondary thrombosis of a branch of a revascularized polar artery. A review of the literature shows that caliceal fistula is an unusual vascular complication which can be avoided by careful removal and meticulous bench surgery. Study of the radionuclides should enable an early and reliable diagnosis. Surgical treatment is needed as soon as the diagnosis is confirmed. Omentoplasty gives the best results.