The aim of this study was to develop a Breastfeeding Support Scale for Couples (BSSC) and to examine its reliability and validity. The BSSC was designed to evaluate current state of mutual support necessary for breastfeeding from the perspective of wife as support recipient, and husband as support provider. Subjects were 324 wives who came for their 1-month postpartum checkup and their husbands. Valid responses obtained from 159 husbands (97.0%) and 303 wives (93.5%) were then subjected to analysis. The BSSC for husbands comprised of 10 questions and two factors, and a scale for wives comprised of 14 questions and three factors were ultimately created. Cronbach's alpha reliability coefficient ranged from 0.72 to 0.89 for all factors for both husbands and wives. The internal consistency and criterion-related validity of the scale were also confirmed. The model fitted the data satisfactory. Its reliability and validity were confirmed. The BSSC focused on mutual support among married couples, and may reveal new directions for breastfeeding support by shedding light on the differences in the perception of reciprocity support. The BSSC can evaluate couples and the appropriate support necessary for breastfeeding from the perspective of reciprocity support. J. Med. Invest. 63: 96-103, February, 2016