The demographic evidence of gender bias in many countries has provided an impetus for finding ways to study the status of women in developing countries. Because of the lack of accurate intra household data, Deaton  introduced a method for using household expenditure data to infer discrimination in the allocation of goods between boys and girls. Few studies of discrimination using the method, however, have detected bias even though alternative indicators suggest it is a serious problem. In this paper, we study the case of Papua New Guinea, a country in which there are many indicators of severe gender bias. Discrimination in the allocation of goods between boys and girls within households in Papua New Guinea is examined using Deaton’s outlay-equivalent ratio method. Adding a boy to the household reduces expenditure on adult goods by as much as would a nine-tenths reduction in total outlay per member, but girls have no effect on adult goods expenditure. The hypothesis of Haddad and Reardon  that gender bias is inversely related to the importance of female labour in agricultural production is not supported. Sensitivity analysis shows that bias in rural areas occurs equally regardless of the age of the household head, while bias against girls may be less in regions of the country that have ethnic groups which practice matrilineal descent.