The purpose of the present study was to determine whether a behavioral economic framework of demand analysis can be used to characterize persistence of breastfeeding. To this end, we developed a novel hypothetical task using likelihood measures to quantify “demand” for breastfeeding. Participants, females aged between 18 and 50 who have given birth in three years, were recruited from Amazon Mechanical Turk. In the demand task with a hypothetical scenario, they returned to work with a baby of 2 months old, and they were asked to rate their likelihood of breastfeeding their baby at a feeding station versus formula-feeding their baby at their desk. The distance to the feeding station ranged from 10 sec to 60 min. This assessment was conducted with and without a financial incentive for breastfeeding. We found that a group of mothers who breastfed for 6 months showed significantly greater intensity and persistence of breastfeeding under both incentive conditions than a group of mothers who did not. We also found that the financial incentive significantly increased intensity and persistence of breastfeeding for the non-breastfeeding group, but no significant increase was observed for the breastfeeding group. Implications from a behavioral economic perspective are discussed.