The Oral Health Impact Profile (OHIP) is a measure of oral-health-related quality of life developed in Australia but being used increasingly in other populations. In view of the culturally specific nature of peoples' perceptions of health, if we are to make between-population comparisons of oral-health-related quality of life, cross-cultural equivalency of the relevant instruments needs to be verified. A study was therefore undertaken to compare item weights generated by an Australian sample with those generated by a sample of English-speaking Canadians and another of French-speaking Canadians. In addition, within-group comparisons by age were performed. The items and subscales used for the 2 Canadian samples were identical to those developed in Australia, although a formal French translation was used for the French-speaking sample. The method used for the generation of weights was Thurstone's paired-comparison technique, based on the judgments of convenience samples of subjects drawn from each of the three cultural settings. Comparisons were made by means of intra-subscale weight rankings and magnitude. Spearman's rank correlations of r> or =0.6 were found for 16/21 between-group comparisons and for 12/21, 19/21, and 8/21 within-group comparisons made by age in Australia, Ontario, and Quebec, respectively. Comparisons of the magnitudes of weights found that, even when items were ranked similarly, magnitudes could be quite different. These results suggest a reasonable degree of cross-cultural consistency, and hence validity, for the OHIP.