Exclusive breastfeeding for the first six months of life is a natural, cost effective and feasible intervention that promotes child survival. Exclusive breastfeeding has been promoted severally but its practice has remained poor in Nigeria. This study aims to determine the knowledge and practice of exclusive breastfeeding among mothers who bring their children to the department of Paediatrics University of Port Harcourt Teaching Hospital. This was a descriptive cross-sectional hospital based study carried out from January 2012 to December 2013. A total of three hundred mothers presenting with their children for treatment at the Department of Paediatrics outpatient clinics, emergency and children medical wards were consecutively recruited into the study. Data on demographics, marital status, socioeconomic characteristics, knowledge and practice of breastfeeding were obtained using a structured self-administered questionnaire. The respondents were aged between 18 and 55years with a mean age of 31.59+6.6years. Most of the women were between 26-35years, majority (39%) were aged 25-30years and majority(89.3%) were married. Thirteen percent had no formal education while majority (63.8%) had tertiary education. Ninety eight percent of the respondents had heard about EBF. Knowledge of the correct meaning of EBF was 91.3% while awareness of the benefits of EBF was 69.3%. Thirty five (11.7%) practiced EBF for the first 6months. More than half (57.7%) of the respondents initiated breastfeeding within 1hour of delivery while 24.7% did so after 1hour but within 24hours of delivery. One hundred and twenty seven (42.3%) of the mothers had given prelacteal feeds to their babies. Of those who gave prelacteal feeds, 8.6% gave plain water, 6.3% glucose water, and 0.3% infant formula and herbs. In conclusion, the practice of exclusive breastfeeding in this study is very low and therefore there is an urgent need to scale up programmes that will promote exclusive breastfeeding in our region.