Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder. In women, the frequency of OSA increases substantially during and after the menopause, as does the prevalence of obesity in this reproductive life stage. This cross-sectional study uses data from the Sao Paulo Epidemiologic Sleep Study (EPISONO, 2007), and comprises a sample of 500 women aged 20-80 years. Multiple logistic regression analysis was used to assess the factors associated with OSA in premenopausal and postmenopausal women. All participants underwent polysomnography, and obesity was assessed using the waist-to-height ratio (WHtR), body mass index, neck and waist circumference, measured using standard methods. WHtR was the factor most associated with a significant increase in risk of OSA in premenopausal women. Waist circumference was the factor most associated with OSA in postmenopausal women, for all severities of the disease. Anthropometric factors presented a high rate of accuracy in the classification of women with OSA. The study found that different obesity-related anthropometric measures should be considered in the diagnosis of OSA, according to the woman's reproductive stage.