Objectives: To study perceived mental stress in relation to oral health among Swedish middle-aged women over a 36-year period, including considerations concerning smoking and socioeconomic status (SES). Methods: This combined medical and dental study includes three cross-sectional (1968/9 N=746, 1980/1 N=432, 2004/5 N=500) surveys of 38- and 50-year-old women included in the Prospective Population Study of Women in Gothenburg, Sweden. Panoramic radiography was used to register the number of teeth, filled teeth and decayed teeth and the level of periodontal bone loss. The information concerning perceived mental stress, smoking and education (chosen to represent SES) was questionnaire-based. Results: Perceived mental stress increased over the 36-year period, but was not related to oral health. The time of examination year had a protective effect on oral health, with a larger number of remaining teeth, fewer decayed teeth and less periodontal bone loss in the later examination year, 2004/5, compared with 1968/9. Risk factors for poor oral health were smoking, greater age (50 vs. 38 years) and low educational level. Smokers had fewer filled teeth than non-smokers except in 2004/5, and there was a shift over time towards fewer filled teeth among highly educated women. Conclusions: A remarkable increase in perceived mental stress was seen among the women over time, but was not associated with oral health. Smoking, greater age and low educational were risk factors for poor oral health, whereas a later examination year was a protective factor. Key words: stress, oral health, women, epidemiology, periodontitis, socioeconomic status, Sweden