Insomnia is a highly prevalent disorder that can lead to substantial impairments in quality of life and functional capacity. This condition occurs significantly more frequently in women than men. An important contributing factor is that insomnia can occur in association with hormonal changes that are unique to women, such as those of menopause or the late-luteal phase of the menstrual cycle. Another consideration is that women are more likely to suffer from major depression and anxiety disorders, which are also associated with insomnia. The reasons are unclear as are the reasons why women are at increased risk of primary insomnia. These conditions are frequently encountered in clinical practice and present a challenge to the practitioner because there is a striking lack of research data to serve as a guide. For example, there are no published studies to indicate how to safely and effectively manage insomnia that often occurs late in pregnancy. This article reviews the available literature related to these conditions with a focus on the epidemiologic data and diagnosis and treatment of insomnia and highlights the need for further research.