Venous thromboembolism (VTE) is known to occur in patients with cancer. Deep vein thrombosis (DVT) in cancer patients can cause pulmonary embolism, and can be a noncancer cause of death. Several studies reported risk factors of DVT in patients with cancer, but correlation of DVT and metastasis of cancer, cancer type, and tumor marker were not fully elucidated. The aim of the present study is to investigate the prevalence of DVT by cancer type, and the relationship between the metastasis of DVT and tumor marker levels in patients with cancer who underwent ultrasonography of the deep veins of the lower extremities.