Painful diabetic distal sensory neuropathy is a disabling and common complication of diabetes mellitus. There is evidence that microvascular changes resulting in ischemia to the vasa nervorum may contribute to this problem. Pentoxifylline has been shown to improve circulation through partially occluded peripheral vessels and has been postulated to be of potential benefit. Forty adult type II diabetics were enrolled in a double-blind, placebo-controlled study utilizing pentoxifylline for six months. Visual analog scores, nerve conduction studies, and physical examinations were used to evaluate response to treatment. At the end of the six-month trial, there was no significant difference in the patients' pain between the pentoxifylline- and placebo-treated groups. The authors conclude that pentoxifylline is not useful in the treatment of painful distal diabetic neuropathy.