The objective of this study was to assess the effect of maternal knowledge and attitude towards dentistry on the oral health status of preschool children in Lagos state. Subjects comprised 404 pairs of mothers and their preschool children in two randomly selected local government areas in Lagos State. The mothers and children were selected from primary health centres and preschools in the each local government area using a multistaged sampling method. Each mother completed a questionnaire that included components assessing her attitude towards her child and her personal oral health as well as testing her oral health knowledge. This was followed by an oral examination of the child. The data recorded included caries prevalence using the “dmft” index and the oral hygiene (OHI) score for each child. A large number of mothers (71.3%) had an average level of knowledge of the issues examined, while 69.8% displayed poor attitude towards oral health. The oral hygiene level of the children was however good with a mean OHI score of 1.29+/- 0.62. The caries prevalence was also found to be low (10.9%) while the mean dmft score was 0.25. There were significant correlations between maternal attitude and the OHI and dmft score as well as between the mothers’ knowledge of oral health care and the child’s OHI score. The better the mother’s knowledge about and attitude towards oral health care the less caries the child had and the better the oral hygiene. This study thus concluded that maternal attitude and knowledge were important determinants of the child’s caries experience and oral cleanliness in preschool children in Lagos State. It is recommended that oral health education and promotion activities should be conducted to improve the maternal knowledge and attitude.