There have been various methods of reducing the lower facial width and one of the most preferably used thchniques was conventional angle resection method with or without masseter muscle resection. However, it is very difficult to achieve a good result in cases with medially impacted mandible angel and thick mandible body because operation field is very limited, in which reduction in terms of A-P view as well as lateral view is not sufficiently done. So, authors performed splitting ostectomy of the mandible angle from August 1997 to April 2000 in 14 patients where all of them is female except one. Age was distributed from 19 years old to 34 years old(mean 25.8 years odl), and follow up study wss made from 3 months to 29 months(mean 13 months). Based on the imaginary transverse line from the occlusal plane of the lower 2nd or 3nd molar tooth, outer cortical osteotomy was made at the mandible ramus to the vertical imaginary line drawn from the sigmoid notch. And then burring was done to make a notch at the outer cortex down to the anadible body just inferior to the second molar tooth. After creating the notch, drilling was done in 2~3 mm intervals where direction was carefully adjusted to reach the inner cortical area with a mandible angel was ostectomized in full layer. At the same time, bony prominence of the body and the irregularity of the mandible angel was burred and smoothened out with electrical bur. No major complications such as infection, hematoma, subcondylar fracture, and nerve and vessel injury were occurred but 1 patient were complained of asymmetry, 1 patient were complained of undercorrection, and residual swelling was more notable compare to conventional angel resection method. Gonial angel increased 5˚~20˚(mean 13˚) and intergonial distance of soft tissue decreased 0.5~2.2cm(mean 1.5cm) postoperatively. Author's method was focused on the improvement of the frontal facial profiles as well as lateral profiles especially in the cases with wide mandibular arch and thick mandibular body and angle was impacted posteromedially. From the long term follow up, more natural and smooth facial contours can be obtained from both the frontal and the lateral profiles in terms of the three-dimensional effects. In this report we describe our experiences with angle splitting ostectomy, which was found to be more effective and safe than the conventional preocedures in reducing the width of the lower face.