Skin flaps are frequently performed for diabetic patients in spite of countless detrimental effects of diabetes on flap survival. This study was planned because only a few clinical experiments have been performed on the effect of pentoxifylline (PTX) on the flaps in diabetic-animals. We studied 4 groups of rats: group 1, diabetic PTX treatment; group 2, diabetic control; group 3, nondiabetic PTX treatment; group 4, nondiabetic control. For the diabetic groups, diabetes mellitus was induced via intraperitoneal injection of streptozotocin (55 mg/kg). For treatment groups, PTX injections were started at the end of the 6th week of the experiment and procedures were carried out for 4 weeks during the experiment. Modified McFarlane flaps were elevated from all animals at the end of the 10th week of the experiment. Surviving areas of the flaps were measured at the end of the 11th week.