A previous study among Amsterdam 5-year-old children showed that on average, the older the child at the onset of toothbrushing and the less frequent the toothbrushing, the more life time caries experience it had. The aim of the present study was to assess correlates of these two caries risk factors, in four ethnic groups. A further aim was to evaluate the putative role of correlates as intervening variables between ethnicity and caries risk factors. Questionnaire data were available from the Amsterdam study, in which a stratified sample of 103 Turkish, 258 Moroccan, 59 Dutch and 56 Surinamese parents were interviewed at home in their mother tongue. Results showed 69 per cent of the Turkish, 45 per cent of the Moroccan, 17 per cent of the Dutch and 11 per cent of the Surinamese parents had commenced brushing their child's teeth only after its second birthday or even never at all. Moreover, many parents had not brushed their child's teeth every day. Almost all potential correlates in six domains, namely parental habits, attitudes, evaluative beliefs, behavioural beliefs, perceived role of the child and that of the partner, were found to be related crudely to the risk factors. Large differences in score patterns on the correlates were observed between ethnic groups. Multiple logistic regression analyses showed substantial parts of the differences in risk factor scores between the Turkish group and a combined Dutch and Surinamese reference group could be attributed to the intervening role of the correlates, as could only minor parts of the difference in risk factor scores between the Moroccan group and the reference group.