Arteriovenous fistulas resulting from cardiac interventional radiological procedures are reported to be rare. Three patients are presented who developed femoral arteriovenous fistulas after cardiac catheterization. The fistulas were discovered incidentally. The patients had symptoms of intermittent claudication which improved after correction of the fistula alone in two patients, suggesting that the fistulas were contributing to the symptoms of claudication. The reported incidence of 0.28% for arteriovenous fistulas after interventional procedures is probably an underestimate because they are often symptomless and only discovered incidentally during examination for another problem. When discovered they should be corrected because they can cause reduction in blood flow to the affected limb and produce symptoms if occlusive disease is already present.