A 58-year-old man was referred for I-131 whole-body scan on day 7 after I-131 ablation to evaluate follicular carcinoma metastases. I-131 whole-body scanning revealed increased uptake in the lower neck representing postoperative residual thyroid tissue. In addition, I-131 uptake in the liver was increased in excess of diffuse physiologic hepatic uptake. Increased superficial I-131 uptake in the left calf suggested contamination. Doppler ultrasonography revealed a dilated left greater saphenous vein in the same region. Dilatation and enlargement of the greater saphenous vein was also shown on radionuclide venography with Tc-99m-labeled red blood cells. I-131 pooling in dilated veins may mimic contamination or metastases.