Several national studies have been undertaken to assess the prevalence of fluorosis utilizing the Dean's Index. However, the latest national study undertaken in 1997 (1) had utilized the DDE Index and hence does not allow comparisons to be made with the earlier set of national data. This cross-sectional study was undertaken to evaluate the prevalence of dental fluorosis using the Dean's Index in a sample of 12-13 year-old schoolchildren and to assess the relationship between fluorosis and their caries status. The sampling procedure involved a multistage, clustered and stratified random sampling. The sample comprised of 1519 schoolchildren attending 20 secondary government and governmentaided schools in fluoridated urban and rural areas of Klang District in Peninsular Malaysia. There were 772 males and 747 females. Each subject was administered a questionnaire to elicit the demographic information. Intra-oral examination for dental fluorosis and caries was performed for each subject. The results demonstrated that more than half of the subjects (54 %) had no fluorosis, 13.2% had questionable fluorosis, 31.3% had very mild to mild fluorosis, 1.4% had moderate fluorosis and only 0.1 % exhibited severe fluorosis. The mouth prevalence was 32.8 %. The Community Fluorosis Index was 0.48 indicating a borderline score for public health significance. Fifty-two percent of the children were caries free. The mean DMFT for all subjects was 1.1, F(0.6) being the main component. Although girls had a higher mean DMFT score as compared to boys this difference was not significant. Significant differences in DMFT scores were observed by urbani rural distributions and ethnic groups (p < 0.01). No significant correlation was found between fluorosis and caries status. It is concluded that dental fluorosis does not appear to be a public health problem. Further coordinated in-depth research using similar criterias for assessing dental fluorosis is highly recommended.