The search for effective strategies to deal with prevention and treatment of oral disease focuses on children as a natural target population. This article reports data on the comparative costs of delivering dental care to children via (1) a school-based practice using Expanded Function Dental Auxiliaries, (2) a school-based practice without EFDAs, and (3) a group of unrelated private dental practices operating independent of the school system. Utilization of a dentist's services varied significantly between the children assigned to private care and those assigned to the school-based programs, but it cost less per patient to provide dental treatment through the private practitioners. If school-based practices are clearly more effective in reducing dental disease, in the long run the need for manpower and resources in these programs might be lowered to a point where they will become more cost-effective than private practices. If the two delivery modes are equally effective in reducing dental disease, however, results from the study indicate that private practices are more cost-effective and will probably maintain their cost-effective advantage over school-based programs.