BACKGROUND: This study was performed to develop, evaluate, and implement an effective obesity intervention program using the DMAIC (Define, Measure, Analyze, Improve, Control) methodology. METHODS: A workplace obesity intervention program involving 100 obese male workers (% body fat > or = 25% and BMI > or = 25 kg/m2) was conducted five times (20~30 minutes each time) for 12 weeks. The intervention involved a face-to-face counseling. RESULTS: The selected critical to quality (CTQ) according to the Define phase was % body fat. The subjects' mean % body fat, measured during Measure phase, was 27.8% and the sigma level was 0.54sigma. According to the analyse phase, the total energy intake (r = 0.417; P < 0.001) and frequency of exercise (r = -0.317; P < 0.01) were considered as potential factors influencing % body fat. Therefore, these factors were implemented in the intervention protocol. By performing six sigma methodologies, % body fat was significantly decreased from 27.8% to 26.2%, and the sigma level was improved from 0.54sigma to 1.27sigma. CONCLUSIONS: The six sigma methodology was well suited for implementing a more efficient and cost-effective intervention, for enhancing the quality of the intervention, and for facilitating the successful adoption of the process and protocol into practice.