All the 1012, 55-yr-old citizens of Oulu (a medium-sized Finnish town) were invited to a clinical examination, and 780 of them participated. The associations of lifestyle with periodontal health were analyzed in the 527 dentate subjects. Periodontal pockets deeper than 3 mm were recorded as a percentage of the surfaces at risk. Lifestyle was measured by questions about dietary habits, smoking habits, alcohol consumption and physical activity. Lifestyle had an independent association with periodontal health. Periodontal pocketing increased with an unhealthier lifestyle. Lifestyle could explain some of the social and sex differences in periodontal health.