Aim This study aimed to develop a Japanese version of the Caregiving Interface Work Scale (J-CIWS) for use with employed Japanese family caregivers. Methods Permission was obtained from the developer of the original CIWS. The CIWS contains 20 items: 10 measuring care interface work (CIW) and 10 measuring work interface care (WIC). Responses are measured on a five-point Likert scale. The J-CIWS was developed through forward- and back-translation and cognitive interviews of employed family caregivers.