The Computerized Registry of Patients with Venous Thromboembolism (RIETE) is a multidisciplinary Project initiated in march 2001 and consisting in obtaining an extensive data registry of consecutive patients with venous thromboembolism. The main objective is to provide information on the Internet to help physicians to improve their knowledge on the natural history of thromboembolic disease, particularly in those subgroups of patients who are usually not recruited in randomized clinical trials (pregnant women, elderly patients, disseminated cancer, severe renal insufficiency, patients with contraindications to anticoagulation therapy, extreme body weight, etc), with the purpose of decreasing mortality, frequency of thromboembolic recurrences as well as bleeding complications and arterial events. As an additional objective RIETE is also aimed to create predictive scores that help physicians to better identify patients with high risk of presenting some of these complications. The primary parameters recorded by the registry comprise details of each patient's clinical status, including any coexisting or underlying conditions, and the type, dose, duration and outcome (during the first 3 months of therapy) of antithrombotic treatment. Study endpoints are clinically recognized (and objectively confirmed) recurrences of VTE, major and minor bleeding complications, and death.