The standardized incidence of cancer in patients with venous thromboembolism (VTE) is about 5%. This risk is higher in patients diagnosed with idiopathic, bilateral or recurrent VTE. The incidence of cancer is the highest within the first year after the VTE and approximately 40% of these cases are already metastatic when diagnosed. Among malignancies presenting with VTE as their first clinical manifestation, cancers from the pancreas, the stomach, the ovary, the lung, the brain or the liver are the most commonly identified. An extensive diagnostic work-up in all patients with unexplained VTE is not cost effective in terms of survival or of quality of life. Cancer screening should be guided by the results of complete clinical examination, blood count and chest X-ray.