Objectives: The purposes of this study were to describe the incidence of root caries and to identify its risk factors in a representative sample of older adults. Methods: Root caries incidence was estimated and multivariate risk assessment models were developed to identify predictors for roof caries in a three-year follow-up study of 234 black and 218 white noninstitutionalized adults aged 65 and older residing in North Carolina. Results: During the observation period, 29 percent of blacks developed root caries, compared to 39 percent of whites (P<.05). The mean net DFS increment per person was 0.55+/-0.13 13 root surfaces for blacks vs 0.80+/-0.21 for whites (P>.32). Multivariate logistic regression analysis indicated that blacks wearing a partial denture, having some roof fragments, having an average gingival recession greater than or equal to 2 mm, and being free of P. intermedia were at greater risk for developing new root caries. The model for whites showed that retired people with their most severe gingival recession greater than or equal to 4 mm, an average probing pocket depth greater than or equal to 2 mm, and faking antihistamines were more likely to develop new lesions. Conclusions: These findings suggest that older blacks had less risk of root caries than whites, and in both groups indicators of poor periodontal status increased the risk of roof caries.