Although considerable progress has been made in the diagnosis of venous thromboembolism, several issues remain that are awaiting a proper solution. Among them are: the respective role of compression ultrasound of the proximal veins and ultrasonography of the entire leg vein system in the diagnostic approach of patients with the clinical suspicion of the first episode of deep venous thrombosis (DVT) of the lower extremities; the safety of managing subgroups of patients with suspected DVT without objective tests, i.e., with the use of pre-test probability scores and D-dimer assays; the role of ultrasonography in the diagnostic approach of patients with suspected ipsilateral recurrent thrombosis; and the role of spiral CT in the diagnostic approach of patients with clinically symptomatic pulmonary embolism.