If an association between venous thromboembolism and malignancy is now well established, there is no consensus about the investigations which should be performed to detect occult malignancy after deep vein thrombosis episode. We investigated the usefulness of systematic abdomino-pelvic ultrasonography in 148 consecutive patients older than 40 with deep vein thrombosis and or pulmonary embolism. Ultrasonography was abnormal in 8 patients (5.4%) and detected only 6 cancers. In 5 cases, clinical examination and laboratory tests were sufficient to suggest malignancy. Our results suggest that ultrasonography should not be systematically performed in patients with deep vein thrombosis. Decisions to performed additional diagnostic tests can be based on the finding of the initial clinical examination, that includes medical history, physical examination, routine laboratory tests and chest-x-ray.