Objectives : Based on data collected from patients who suffered from dental caries during the period between 1990 and 2008, the number of patients and their trends were analyzed as a source of evidence to conduct the oral health plan. Methods : A population of sample design for patient survey data was derived from computerized data saved at medical institutions accredited by National Health Insurance Corporation. Large institutions such as dental hospitals were included for the complete enumeration test, while the rest of medical institutions, for example, dental clinic, relatively small institutions, were used for the sample survey. Most of patients with dental caries were outpatients and their disease was treated at the dental hospital or dental clinic in general, therefore, main analysis was carried out at those institutions. Results : The rate of patients who suffered the dental caries has decreased to 56.8% in 2008 from 78.5% in 1990. The rate of patients who visited the dental hospital for treatment has increased to 4.8% in 2008 from 0.5% in 1990, whereas the percentage of those who visited the dental clinic has fallen to 97.9% from 99.5% during the same period. The ratio by age, in the meantime, it showed that patients aged 40s has increased to 13.5% in 2008 from 7.2% in 1990, and the number also has risen in 50s from 5.6% in 1990 to 9.9% in 2008. However, the number of children aged 0 to 9 who visited hospital for treatment of dental caries has fallen to 17.0% in 2008 from 33.9% in 1990. Conclusions : By figuring out the trends of patients with the dental caries during the period between 1990 and 2008, fundamental data for the oral health policy have been collected. As a result, the necessity of a new medical treatment system for managing the dental caries in terms of patient ages as well as the oral health policy and campaign was taken into consideration.