The width of the calcaneal fat pad during weightbearing differs from its width during nonweightbearing. In this study, the medial-to-lateral width of the calcaneal fat pad was measured during weightbearing as well as nonweightbearing, and the two measurements were compared. The difference between weightbearing width and nonweightbearing width was found to vary widely across individuals. This measurement has implications for the manufacture of functional foot orthoses, which are made from nonweightbearing impressions of the foot. The significance of the authors' findings with regard to patient comfort is discussed.