In order to determine whether cognitive performance is influenced by the menopausal transition, we tested cognitive performance at three time points, sampled women in earlier as well as later stages of the menopausal transition (40-65 years of age), and assessed the moderating influence of body mass index (BMI) on rate of change. Multilevel analyses were used to model change in cognitive performance as a function of number of years post menopause over and above chronological age. We investigated change in the menopausal transition for 10 cognitive outcomes in 193 women who were postmenopausal during the last test wave. The model, controlling for age and education, showed that postmenopausal women within the normal range of BMI (BMI 18.5-25) displayed more rapid decline than women with BMI above 25 for measures of visuospatial ability and episodic memory. In addition, there was an accelerated rate of change post menopause for all women on verbal fluency. The results support the notion that the diminished postmenopausal production of endogenous estrogen may have a slight negative influence on cognitive abilities, but mainly for women within a normal BMI range.