Objectives. Exclusive breastfeeding for the first 6 months of life is still rare among nursing mothers. This study aimed to identify the factors influencing breastfeeding practices among mothers in Anambra State, Nigeria. Methods. A prospective cohort study was conducted in three comprehensive health centres of Nnamdi Azikiwe University Teaching Hospital (NAUTH), Anambra State, between September 2006 and June 2007. The breastfeeding practices of 228 nursing mothers were assessed at enrolment when attending the maternal and child welfare clinics for BCG immunisation, and at follow-up visits at 6, 10, 14, 20 and 24 weeks. In addition, four focus group discussion sessions (one in each centre) were held, involving a total of 35 nursing mothers. Results. Most mothers 190 (83.3%) were aged between 20 and 34 years. The majority (208, 91.2%) had good or very good knowledge of breastfeeding. The main source of breastfeeding education was government health facilities (80.85%), but only 110 mothers (48.2%) initiated breastfeeding immediately (<1 hour) after delivery. The exclusive breastfeeding (EBF) rate fell from 143 (62.7%) at birth to 85 (37.3%) at 24 weeks. EBF was significantly associated with older maternal age, higher parity, delivery at a government facility, a positive family attitude towards EBF, and breastfeeding education from a government health facility (p<0.05). Focus group discussion showed that mothers believed that adequate nutrition and physical, financial and emotional support to them would increase EBF practice. Conclusion. The rate of EBF was low among the mothers, and the factors identified that may influence its practice have important implications for breastfeeding intervention programmes. Activities to promote EBF should be focused on specific groups of women and locations in which it is poorly practised. In addition, support to the mothers is necessary.