The aim of this study was to explore the association between oral health and obesity. The study was conducted in the spring of 2007 as a postal survey of all inhabitants born in 1942 and living in the two Swedish counties of Örebro and Östergötland. This questionnaire survey has been conducted every five years since 1992 but has been updated continually with additional questions and for the sweep used here, height and weight data were collected. A total of 8,313 individuals received the questionnaire and 6,078 of those responded (73,1%).The outcome variable oral health was measured using one global question and four detailed questions representing different aspects of oral health. The independent variable Body Mass Index (BMI) was calculated using self-reported height and weight. A difference in oral health between various BMI groups was found. The difference was both statistically significant and of clinical importance, particularly among the group with severe obesity who reported poorer self-perceived chewing capacity lower satisfaction with dental appearance, increased mouth dryness and fewer teeth and lower overall satisfaction with oral health. In view of the increased risk of poor oral health demonstrated in this study for those with severe obesity, it may be of value to increase cooperation between dental care and primary health care for these patients.