Thrombus of the renal vein or inferior vena cava is a known complication of renal cell carcinoma (RCC). Accurate discrimination between bland and malignant thrombus can have significant implications toward clinical management. Distinguishing between these 2 entities is not usually possible with enhanced computerized tomography (CT) or magnetic resonance imaging. This case reports the role of combined positron emission tomography-CT imaging in the accurate detection of recurrent RCC after partial nephrectomy and surgically proven tumor thrombus in the renal vein and inferior vena cava.