Four hundred and forty-six children attending nursery schools in Nairobi were examined for caries and gingivitis. Assessment of social class was based on the occupation of the head of the child's household. Amongst 3-year-old children, 62% were caries-free and the mean dmft was 1.35. Amongst 5-year-olds 50% were caries-free and the mean dmft was 1.88. Thirty-seven per cent of the children had evidence of gingivitis, with the proportion changing little with age. There was no evidence of either caries or gingivitis being significantly related to social class, although children in the higher classes had more filled teeth.