Most studies related to addressing weight management of obese children have focused on understanding the perceptions of parents and health professionals. This study identifies the factors that obese children who have tried to lose weight perceive as affecting their efforts. This descriptive qualitative study has sought to identify factors affecting obese children's weight-loss decision making and process and to explore the development of an effective weight-loss program. This study screened 603 primary school children equivalent to U.S. Grades 5 and 6 of age 10-12. Seventy-nine out of 93 obese children who had been trying on their own to lose weight for at least 1 month formed 6 focus groups. Four themes were identified: Making the decision, self-efficacy, social influences, and environmental constraints. The results suggest that the design of a weight-loss program for obese children should include the contribution of family members, school, and health professionals. (Contains 1 table and 2 figures.)