Epidemiologic studies have shown that root surface caries are present worldwide. The prevalence and incidence of root surface caries differ widely among different populations but also among individuals within the same group. Differences in diagnostic criterias and reporting of data substantially influence epidemiologic data. The prevalence of decayed and filled root surfaces generally increases with age. However, age per se is not considered to be the main reason for caries development on root surfaces. The same main factors as for coronal caries, ie, cariogenic microorganisms, diet, saliva, and fluoride exposure, seem to play important roles in root caries development. Due to different anatomy, histology, and chemical composition of the tissues, there may be a higher risk of caries development on root surfaces than on coronal surfaces. In treatment of root surface caries, a causative treatment strategy should be determined. Prevention and treatment should focus on oral hygiene, fluoride exposure, and restriction of intake frequency of foods containing sugars or other easily fermentable carbohydrates.