Indiana University-Purdue University Indianapolis (IUPUI) / In 1973 the state of Indiana initiated a program to fluoridate the water in rural school systems to a concentration of 4.0 ppm. Today, the optimal concentration is 3.5 ppm. When it was initiated, school water fluoridation was a popular method of providing fluoride supplementation to children who didn't have access to community-fluoridated water. Today, only Indiana runs a school water fluoridation program, and the CDC has stated that continuation of these efforts should be based on caries risk, alternate preventive measures, and periodic evaluation of program effectiveness. The purpose of this study was to assess the efficacy of the Indiana school water fluoridation program in order to determine if children participating in the program develop less caries with no increased risk of fluorosis. Four hundred sixty students were examined from Northwestern Consolidated School Corporation in Shelby County (fluoridated school) and North Knox School Corporation in Knox County (non-fluoridated school). Three hundred ninety-one students were statistically evaluated, 204 from the fluoridated school and 187 from the non-fluoridated school. A thorough visual examination was conducted by the same examiner collecting data on DMFS, defs, and fluorosis in grades 1-6. DMFS scores were 28 percent less for fluoridated students compared with non-fluoridated students (0.95 versus 1.32). Although the effect of fluoridation status on caries in permanent teeth is not statistically significant, the author believes this difference may be clinically significant. Analysis of defs scores showed fluoridated students with 6 percent less defs than non-fluoridated students, although the results were not statistically significant. Only 3.92 percent of the students at the fluoridated school showed fluorosis, while 10.16 percent showed signs of mild fluorosis at the non-fluoridated school. Conclusion: While not statistically significant, children attending the school fluoridated with 3.5 ppm of fluoride developed less caries and suffered no increase of fluorosis compared with children attending schools not participating in the school fluoridation program. Further analysis is necessary through statewide blind examinations at numerous school systems to further assess the efficacy of the Indiana School Water Fluoridation Program.