Examination of the literature, reviews with experts, and one-on-one interviews with women who had experience combining breastfeeding and work were used to create the instrument subscales and items. Examination of the literature was used to develop four subscales: company policies/work culture, manager support, co-worker support, and workflow. Expert review resulted in the addition of a fifth subscale, the physical environment of the breastfeeding space. One-on-one interviews were used to ensure that the item wording was appropriate for the target population.