One thousand five Hong Kong kindergarten children with a mean age of 5.75 +/- 0.46 years were sampled for caries prevalence and related factors. Samples were drawn from a total population of approximately 9,000 5-year-old children. Caries examination was conducted after the teeth were cleaned professionally using a sickle probe (Ash #54) and diagnostic criteria of the World Health Organization. Thirty-seven percent of children were caries-free and the mean dmft of all children was 3.2 +/- 3.92. The components of the dmft were dt = 2.93, mt = 0.04 and ft = 0.23. The dmfs was 5.10 +/- 7.80 with ds = 4.67, ms = 0.12, and fs = 0.31. The caries distribution was skewed, 18% with more than 10 dmfs and the most severely affected child having 54 decayed surfaces. Seventy-two per cent had never visited a dentist. A statistically significant positive correlation was found between the father's profession and caries prevalence. The age of the child at the first visit and the frequency of visits to the dentist were related directly to parental income. The primary mandibular first molar ranked highest among the teeth that needed treatment, mostly extraction. (Pediatr Dent 15: 116-19, 1993).