PURPOSE: To study the effectiveness of the ultrasound and LASER on the fracturehealing in rabbits. MATERIALS AND METHODS: This study was performed on rabbits using the Hi-Tech 2000 (Ultrasound+LASER) which was made in our institute. After anesthesia of the rabbit, the shaft of tibia was fractured with Gigli saw under aseptic condition, and then intramedullary nailing using K-wire was performed. We evaluated left tibia as control and right tibia as experimental. we applicated ultrasound and LASER from 7 days after operation and sacrificed at 3 weeks and 5 weeks after operation. Gross findings, simple radiologic findings, and histologic findings were evaluated by modified Zorlu scoring system. With use of T-test of SAS system ( level of significance, P < 0.05 ), difference between left and right tibia were evaluated to be determined the effect of ultrasound and LASER on the fracture-healing. RESULTS: At postoperative 3 weeks, differences were noted in 4 cases but we could detect no significant difference between left and right side. At postoperative 5 weeks, differences were noted 6 cases and significant difference was noted. CONCLUSIONS: Seeing this results, ultrasound and LASER treatment was effective in fracture healing. However we think that additional studies for accurate quantitative and qualitative analysis, biomechanical test in callus, microangiographic study and clinical research to determine the effectiveness of ultrasound and LASER in clinical field are needed.