Upper extremity thrombosis is responsible for 1-2% of all cases of deep venous thrombophlebitis (DVT). Little has changed concerning the clinical presentation, diagnostic investigation, or treatment of the disorder over the last forty years. However, a changing pattern in the natural history of the disease seems to be emerging with the advent of more invasive procedures and prolonged medical care of critically-ill individuals. Case histories of sixteen (16) patients with seventeen (17) episodes of upper extremity thrombosis are reviewed. Fewer cases of "primary" thrombosis, and fewer acute or chronic sequelae were noted in the present study than would be implied in previous reviews of the subject. It is our opinion that DVT of the upper extremity, especially when due to "secondary" thrombosis, is a more benign and self-limiting disease than has been traditionally reported.