Thromboembolic complications represent one of the most important cause of morbidity and mortality in cancer patients. Although several data have been published demonstrating the strong association between cancer and venous thromboembolism (VTE), there is poor perception, among oncologists, of the level of risk of thrombosis and of relevance of managing VTE in these patients. The Associazione Italiana di Oncologia Medica (AIOM) has provided some recommendations to direct clinical practice according to evidence-based data concerning cancer and VTE. In fact, we conducted an extensive literature review (1996-2005) to produce evidence-based recommendations to improve perceptions of the magnitude of this risk among Italian medical and surgical oncologists and alert on the new approaches to prophylaxis and treatment of VTE in cancer patients. Levels of evidence are given according to a five-point rating system, and similarly for each key recommendation a five-point rating system suggests if the evidence is strong and indicate that the benefits do, or do not, outweigh risks and burden.