This research analyzes the factors influencing choice and the determinants of women's health services demand. Demand for health services in Colombia is practically unexplored, and there appear to be no studies of demand for health services by women of child rearing age in Colombia. The Colombian National Health Study of 1980 (Estudio Nacional de Salud-1980) is the data base used, supplemented by hospital data from the Ministry of Health. After a description of the Colombian Health System, the choice between traditional and modern care is studied for prenatal care, and for child's delivery assistance, emphasizing differences among insured and non-insured women. The first part of the study estimates demand schedules through a logistic specification. The choice of institutional setting for child's delivery assistance, conditional upon the prior decision of using modern care, is studied through a nested multinomial logit specification for women in different regions of the country and for urban and rural women as well. Expected prices for a delivery are estimated for all choices women face. Only few recent studies have found demand for modern health services to be price elastic and dependent on income level; this is also the case in some of the regions of Colombia. Moreover, demand for health services becomes less price elastic as income increases. Demand for Private care is generally more price elastic than demand for other types of care, and in some cases demand for Public care is significantly price elastic at lower income levels. Lower income women rely on Public hospitals when they have decided against traditional care. Then, price changes for Public care would have larger welfare effects on lower income groups. Urban women of high income groups often use Public care, indicating that government subsidies are favoring better-off sectors of the population. Meanwhile, rural women rely heavily on home care, even at higher income levels. A more rational price system for services at social security hospitals would not reduce significantly women's welfare; higher prices would help to provide better quality services and/or permit cost recovery for those institutions which very often find themselves in financial trouble.