OBJECTIVE: To study the incidence and prevalence of breast-feeding and to determine the factors that influence the mother's decision to breast-feed or to use adapted milk. MATERIAL AND METHODS: Two hundred families were included in a survey in the hospital's maternity department. Those who breast-fed were followed up by means of a telephone call on days 15, 30, 90, and 180. RESULTS: On leaving hospital 78% of the neonates were receiving breast milk only. After 15 days, 89.7% of the neonates continued to receive breast milk and at 6 months this figure was 39%. Breast-feeding was discontinued after a mean of 2.5 months. The mean age of mothers who breast-fed was 30.2 years and that of mothers using adapted milk was 27.9 years (p,0.05). Mothers decided on the type of feeding before pregnancy (52.5%). This decision was unchanged by prenatal information except in the case of information provided by the family, especially if both parents were breast-fed (p,0.05). Doctors provided little information. The mother's level of education did not influence the decision to breast-feed although the higher the mother's education, the greater the tendency to breast-feed (74.7% with primary education vs 81.5% with higher education). Being in paid employment did not influence the decision to breast-feed (76% of mothers worked vs 79% of mothers who did not). The main reasons for discontinuance were hypogalactia, "feeling hungry", and work. In general, giving up breast-feeding was the mother's decision. CONCLUSIONS: The information pregnant women receive on breast-feeding should be based on unified criteria. The implementation of joint protocols between primary and hospital care as well as breast-feeding support groups help mothers to begin and continue breast-feeding.