Deep vein thrombosis (DVT) of the arm unrelated to central venous cannulation is an uncommon occurrence in patients with malignancy. The author reports six cases encountered in a large county hospital over an 8-year period. Three of the patients had gastric carcinoma, esophageal adenocarcinoma, and testicular carcinoma, respectively. These neoplasms have not been previously reported to be associated with DVT of the arm. Three episodes of DVT resulted from venous compression by the tumor, and a hypercoagulable state may have contributed to the pathogenesis of DVT in the other three cases. Venography is required for confirmation of the diagnosis; however, a computed tomographic scan with contrast media may be a valuable adjunct. A review of the literature indicated that the incidence of pulmonary embolism is significant in these patients. Therefore, anticoagulation within 7 days of clinical onset is recommended.