During the last decade, a continuous decrease in dental caries has been observed among schoolchildren in Iceland. In this paper, various epidemiological studies have been reviewed and summarized to illustrate caries prevalence, and how it has changed during the last decades. Furthermore, an attempt has been made to describe some of the factors involved and their possible effects on caries disease. During this period, sugar consumption increased, especially in the form of sweets and soft drinks. At the same time, the import of toothpaste increased, and preventive measures such as fissure sealants and fluoride rinsing programs were intensified. Other factors likely to have had an impact were changes in treatment philosophy and increased personnel resources. There does not seem to be any single factor responsible for the onset of the caries decline. It rather looks as if this was a multifactorial effect due to a number of different preventive measures. During recent years, a change in treatment philosophy, the evident increase in fluoride toothpaste consumption, and possible changes in the oral microbial flora, together with the use of fluoride varnishes, sealants, and increased manpower, may explain the decline.