The association between venous thromboembolism (VTE) and malignancy was first recognized more than 135 years ago. Since then, a markedly increased incidence of VTE has been found in patients with malignant disease. Numerous clinical studies have demonstrated that malignancy or its treatment are major risk factors for VTE. Recent developments in moleculobiological studies have indicated that the high risk of VTE in malignancy is attributed to the hypercoagulable state caused by the disease and its treatments. Diagnostic approaches to clinically suspected VTE continue to evolve, making the diagnosis easier and more accurate. Recent advances in clinical studies have refined the management strategies for the prophylaxis and treatment of VTE in patients with or without cancer. In this paper, recent clinical studies will be reviewed, current understanding of the pathogenesis of thrombosis in malignancy described, and clinical implications discussed.