SUMMARY:The aim of this study is evaluate the efficacy of 904 nm laser diode in bone regeneration in the bone defect in diabetic rats. Six groups of 10 male Wistar rats and 2 mm bone defects drilled on the left and right tibia were used. The diabetic animals were treated with streptozotocin (40 mg/kg, i.v.). We compared the diode laser doses of treatment of bone defects 50 w -4 J/cm and 100 w -4J/. The right tibia was used for immunohistochemical analysis with the apoptosis markers XIAP and Caspase-3 and the left tibia was submitted to computer tomography (CT). Caspase-3 marker showed greater amount of apoptosis in all the untreated groups compared to both laser treatments. There was no statistical significance for XIAP marker. CT scan showed improvement of bone defect area and volume in both laser treated groups, control and diabetic. Therefore the low intensity laser therapy was effective in accelerating bone repair in both, control and diabetic groups. It was evidenced in our study that diabetes influences bone repair negatively.