The prevalence and distribution of dental caries was studied in 820 Nigerians aged 15, 19, 20 or 21 years from Lagos educational establishments. In contrast with observations in most Western countries, caries experience in Lagos was observed to be low, the mean DMF value being less than 2 at all ages. Irrespective of age, sex, tribe or social class, the ratio of DFS to DFT was constant at about 1.3, while the mean DMF value remained constant at between 3 and 4 in those persons with at least one tooth decayed, missing or filled. Furthermore, the caries vulnerability difference between first and second permanent molars was independent of the jaw affected or social class.