Knowledge of the advantages of breastfeeding, the disadvantages of bottle feeding and the Papua New Guinean legislation to protect breastfeeding was determined in a comparative study of nulliparous and parous women attending the Antenatal Clinic of Port Moresby General Hospital. A high proportion (40%) of both groups had had experience of bottle feeding. Whilst the large majority (94%) of the women indicated that breastfeeding was the best way to feed babies, knowledge of the reasons for its superiority over bottle feeding and of the dangers of bottle feeding was poor in both groups. Knowledge of the legislation to protect breastfeeding was also poor and was the only area in which there was a significant difference between the groups, nulliparous women having poorer knowledge (p = 0.015). The level of education did not appear to be associated with knowledge about feeding. There is an urgent need to review the legislation, to find ways of enforcing it, and to improve the education of young people on issues of infant feeding.