Background: Excessive body mass is a key risk factor of type 2 diabetes. The aim of the study was to analyse selected determinants of the BMI (body mass index) in women aged 40–65 with type 2 diabetes from the Krakow population. The predictive model includes demographic (age), health (duration of diabetes) as well as behavioural (volume of physical activity) and psychological (life satisfaction) data. Material and methods: ‪The study was conducted among a group of 276 women aged 40–65 (47.92±5.53) with type 2 diabetes. The authors used a specially designed questionnaire, which included socio-demographic questions as well as self-assessment of the health status, the duration of diabetes and the volume of recreational physical activity per week. The standardised Satisfaction with Life Scale (SWLS), originally by E. Diener, R.A. Emmons, R.J. Larsen and S. Griffin, and adapted by Z. Juczyński, was used. The BMI value of women was assessed based on measurements of somatic indicators (body mass and height) using standard measuring tools (Tanita 300-P and an altimeter). Statistical analysis was performed using Pearson's r correlation coefficient, hierarchical regression and moderation analysis using the SPSS programme, assuming the statistical significance level of α=0.05. Results: ‪The mean BMI for women aged 40–65 with type 2 diabetes was 26.71 (±4.14) kg/m2. Correlation analysis showed an increase in BMI along with age and disease duration, and a decrease along with an increase in the women’s life satisfaction. Detailed analysis of the interactional impact of variables on the BMI confirmed the increase in BMI along with duration of the disease, and with the low level of life satisfaction and low and average volume of physical activity (especially in women with low levels of life satisfaction). A decrease in BMI was noted along with an increase in the volume of weekly physical activity (regardless of age). Conclusions: ‪The values of the index in women aged 40–65 with type 2 diabetes seem to demonstrate significant correlations with age, duration of the disease, volume of physical activity and level of life satisfaction, with an indication of the interactive and moderating influence of some variables.