Mortality decline has been assumed to play an important role in fertility transitions. Demographers often attempt to explain the correlation between these phenomena by “rational reproductive decision-making” on the part of individual actors, an idea which follows on from theories developed out of quantitative associations and analyses. In this study, we use qualitative data from rural and urban sites in Senegal to consider the degree to which plausible demographic hypotheses are borne out in people’s discourse on reproductive decision-making. In-depth interviews with men and women are used to examine awareness and conscious reasoning about both replacement and insurance motivations, perception of mortality and other risks in relation to childbearing and the extent to which people have the agency to act upon their perceptions. The limited evidence of explicit replacement and insurance strategies suggest their impact on fertility in Wolof Senegal is small, even amongst the urban educated elite for whom costs of children in terms of money and parental time are much more important constraints. Child mortality is not a major component of the fertility decision-making discourse.