Background: Although sleep disturbances are common during female mid-life, few studies have described in detail the prevalence of this problem and related risk factors. Objective: To determine the prevalence of sleep disturbances in mid-aged women using validated tools. Assessment of determinants capable of influencing the prevalence of insomnia and poor sleep quality was also performed. Methods: A total of 6079 women aged 40-59 of 11 Latin American countries were invited to fill out the Athens Insomnia Scale (AIS), the Pittsburgh Sleep Quality Index (PSQI), the Goldberg Anxiety and Depression Scale, the Menopause Rating Scale (MRS), the Brief Scale of Abnormal Drinking and a general socio-demographic questionnaire. Results: Overall, 56.6% of surveyed women suffered of either insomnia, poor sleep quality, or both. Specifically, 43.6% and 46.2% presented insomnia and poor sleep quality in accordance to the AIS and the PSQI respectively. The prevalence of insomnia increased with female age (from 39.7% in those aged 40-44 to 45.2% in those aged 55-59, p < 0.0001) and menopausal stage (from 39.5% in premenopausal aged 40-44 to 46.3% in late postmenopausal ones, p < 0.0001). "Awakening during the night" (AIS: Item 2) was the most highly rated of all items and contributing in a higher degree (mean 16%) to the total score of the scale in all menopausal phases. Sleep quality also worsened with age and menopausal status, impairment particularly affecting sleep efficiency and latency and the increased use of hypnotics. Vasomotor symptoms (VMS), depressive mood and anxiety were associated to sleep disturbances. Women presenting sleep disturbances displayed a 2-fold increase in the severity of menopausal symptoms (higher total MRS scores) which was translated into a 6-8 times higher risk of impaired quality of life. Logistic regression analysis determined that female age, the presence of chronic disease, troublesome drinking, anxiety, depression, VMS, drug use (hypnotics and hormone therapy) were significant risk factors related to the presence of sleep disturbances. Higher educational level related to less insomnia and better sleep quality. Conclusion: Insomnia and poor sleep quality were highly prevalent in this mid-aged female sample in which the influence of age and the menopause was only modest and rather linked to menopausal symptoms already occurring since the premenopause.