Dental caries is the most common oral disease in the world, and in developed nations, it affects almost everyone. Worldwide, large variations in the trends with regard to the prevalence and the severity of dental caries have been reported. In South Africa, numerous studies to determine the caries prevalence and severity of different population groups have been carried out in the past. However, only three studies were conducted on a national scale; Williams in 19842 reported on the dental health status of 12-year-old children representing the whole country, the National Department of Health conducted a National Oral Health Survey in 1988/19893 to determine the oral health status of adults and children in the five major metropolitan areas in South Africa, and the most recent National Oral Health Survey was conducted during the period July 1999 to June 20024 and was restricted to 4- to 5- year-, 6-year-, 12-year and 15-year-old children in South Africa. The aim of this study was to determine the trends in dental caries prevalence and severity amongst South African children over a period of time by comparing the results obtained from the 1982/1983 National Oral Health Survey with results obtained from the 1988/1989 National Oral Health Survey and/or with results obtained from the 1999/2002 National Oral Health Survey. The statistical methods employed, appeared to be useful to determine the trends in dental caries prevalence and severity amongst South African children, over the period 1982 to 2002, in selected (identified) geographical locations and also in terms of age, race and gender. Although it became evident, through this research, that there is a decline in the prevalence of dental caries amongst all the population groups, from 1982 to 2002, Coloured children presented with a relatively higher prevalence and severity of dental caries when compared with Asian, Black and White children in South Africa. The results mainly showed a higher prevalence and severity of dental caries in the primary than permanent dentition amongst 6-year-old children; and there was also a significant increase in the prevalence and severity of dental caries from the 12-year-old to the 15-year-old group. Through this research, it became evident that there is higher dental caries prevalence and severity rates in the coastal regions (Metro Cape, Port Elizabeth and Durban) as compared to an interior region (Bloemfontein). It was also observed that although the severity (dmft/DMFT) of dental caries decreased during the past 20 years; the percentage of untreated caries in 12-year and 15-year-old children increased; however, at the same time the percentage of untreated caries in 6-year-old children decreased. It was found that the number of filled teeth (FT) contributes the most to the caries experience amongst 12-year- and 15-year-old White children. However, more than 70 percent of dental caries, in 6-year-, 12-year- and 15-year-old children, go untreated. These results obtained from this study entitled: Trends in dental caries prevalence and severity in South Africa; can be useful in attempting to design intervention strategies to address dental caries in South Africa. / Dissertation (MSc (Odont))--University of Pretoria, 2007. / Community Dentistry / MSc (Odont) / unrestricted