Breast-feeding is the focus of rapidly growing interest. Research on the determinants of breast-feeding is only beginning. The research in this paper is based on World Fertility Survey data for Sri Lanka. We develop what we believe to be an appropriate probit model and find that there are significant socioeconomic factors that influence breast-feeding, in addition to the demographic factors focused upon in the literature. Moreover, some of them have clear policy implications, which are elaborated herein with respect to labor force, education, family planning and internal migration policies. In the course of the paper we also address a number of generally neglected statistical issues that should be considered in analyzing the determinants of breastfeeding, including problems resulting from digit preference or age heaping, the need to use dichotomous dependent variables, unavoidable truncation biases in the basic data, and structural shifts in the determinants of breastfeeding at different durations.