This paper reports on two studies exploring similarities and contrasts in knowledge, attitudes and opinions on fluorides and fluoridation of two culturally different population groups. The first study compares the attitudes and opinions of parents of primary (elementary) schoolchildren in Melbourne, Australia, and Yokohama, Japan, and the second study compares the attitudes and opinions of dentists drawn from the same geographic areas. A self-administered questionnaire collected data on 517 parents and 629 dentists. The questionnaires were of similar design and content for both parents and dentists. They included a series of knowledge and attitudinal statements on preventive dentistry and use of fluorides. Attitudinal responses were measured on a 5-point agree-disagree Likert scale. Data were analyzed using both bivariate and multivariate techniques. Australian parents appeared better informed on the benefits of water fluoridation and held more favorable opinions on fluorides and fluoridation than their Japanese counterparts. Similarly, Australian dentists held more positive attitudes toward the use of fluorides and fluoridation than their Japanese peers. Cultural norms and experiences appear to shape parental attitudes, whereas the focus of dental education and dental practice on restorative treatments in Japan appears to be a substantial influence on the attitudes and opinions held by Japanese dentists.