Risk factors for poor dental health include obesity, low socio-economic status, poor dietary habits, and dental anxiety. The aim of this study was to explore the complex relation between body mass index (BMI) and number of teeth in middle-aged women taking education, dietary intake patterns, dental care utilization, and dental anxiety into account. Three groups of women (37-60 years): reference women (group I, BMI 23.8 +/- 3.1 kg/m2), obese women (group II, BMI 35.0 +/- 2.6 kg/m2), and severely obese women (group III, BMI 41.0 +/- 3.4 kg/m2) were included. Questionnaires were used to assess education, smoking, number of teeth, dental care utilization, dental anxiety, dietary intake, and meal patterns. Age, education, and smoking habits did not differ significantly between groups. However, there were significant global differences in number of teeth (27.2 +/- 3.4, 23.0 +/- 9.2, 24.7 +/- 5.9) and reported daily energy intake (9756 +/- 3363 kJ, 10344 +/- 3850 kJ, 11970 +/- 3786 kJ in groups I, II, and m, respectively). In a multiple regression model, a lower number of teeth was independently associated with higher age, higher BMI, lower education, irregular dental care, high dental anxiety, higher energy intake, and lower iron intake. These variables explained 25% of the variation in number of teeth. In conclusion, BMI is an independent predictor of number of teeth in middle-aged women when socio-economic, dietary, and psychological factors are taken into account.