Incidence rates for new root caries and new coronal caries in noninstitutionalized older adults are unknown. In this study, a representative sample of 451 elderly Iowans received dental examinations at the start of the study and again after 18 months. This dentate cohort had a mean of 0.87 new surfaces of coronal decay per person per year and a mean of 0.57 new surfaces of root decay per person per year. Coronal caries occurred at an annual rate of 1.4 surfaces per 100 susceptible coronal surfaces. Root caries occurred at an annual rate of 2.6 surfaces per 100 susceptible root surfaces. This study shows that both coronal and root caries were active in this older population, indicating a need for emphasis on the prevention and treatment of dental caries in older adults.