A descriptive epidemiologic survey of root caries in 473 20- to 64-year-olds revealed an age- and sex-adjusted overall root caries index (RCI) rate of 11.4% indicating that approximately one in nine surfaces with recession exhibited root caries. Although age-adjusted RCI rates for males and females were similar, the sex-adjusted RCI rates for each decade of life between 20 and 60 increased from 1.1% to 4.7% to 13.0% to 22.0%. Intraoral distribution patterns for root caries revealed that the most frequently attacked tooth types were mandibular molars (RCI = 40%), mandibular premolars (RCI = 25%) and maxillary canines (RCI = 23%). The least frequently attacked tooth types were the mandibular incisors (RCI = 2%). The interproximal surfaces exhibited the highest RCI rates in the maxillary arch while the buccal surfaces showed the highest RCI rates in the mandibular arch.