PURPOSE: A lower facial contouring surgery has become a commonly performed procedure in Asia. Currently, mandibular angle sagittal ostectomy and botulinum toxin type A treatment are main procedures for aesthetic correction of a broad lower face. There are a few data to show the differences in the mandibular contouring changes between mandibular angle splitting ostectomy and botulinum toxin type A treatment. Facial golden mask is easy to apply, inexpensive, and relatively objective in evaluating facial contour analysis. This study was designed specifically to compare the changes in lower face width after two different forms of lower facial contouring procedure using facial golden mask. METHODS: Seventeen patients, with the ages ranged from 18 to 55 years(mean, 28.6 years), 15 women and 2 men, consented to the study and receive a contouring procedure of lower face. The patients were classified into 2 groups. In group A, the sample consisted of 10 patients with a prominent squared mandibular angle and mandibular angle splitting ostectomy was performed. In group B, the sample consisted of 7 patients with masseteric hypertrophy and botulinum toxin type A treatment was performed. Photographs of the face were taken to record the facial change at preoperative and postoperative. The postoperative photographs were taken to considered maximal effect in 2 years after the surgery in group A, and 4.8 months after the treatment in group B. The authors applied the facial golden mask to preoperative and postoperative photographs and horizontal ratio, which compares facial width with golden mask width, were calculated. We made an analysis of the result of horizontal ratio using SPSS. RESULTS: Overall average horizontal ratio of pre- and postoperative photos of group A were 1.24 and 1.11, whereas overall average horizontal ratio of pre- and postoperative photos of group B were 1.19 and 1.12. The horizontal ratio decreased 10.24% in group A and 5.93% in group B. There was a statistically significant changes in before and after treatment, but there was no significant change in comparing the group A and group B. CONCLUSION: The results from this study suggest that mandibular angle sagittal ostectomy and botulinum toxin type A treatment showed relatively satisfactory clinical effects on lower facial contouring treatment. There were no statistical significant differences within two lower facial contouring treatment. Facial golden mask is easy to apply, inexpensive, and relatively objective, so we think that facial golden mask is a good method for evaluation of lower facial contouring treatment.