Evaluate the subjective experience of the disease and its treatment in the partners of young women with non-metastatic breast cancer The impact of the disease experience on the quality of life of the relatives of patients with cancer is now well documented. However, few scales specifically address the partners' subjective quality of life. This study aims to validate a questionnaire assessing the impact of cancer on the quality of life of the partners of young women with breast cancer. Partners (n = 499) of women aged <45 when diagnosed with a non-metastatic breast cancer completed a self-reported questionnaire generated from non-directive interviews led in an initial study. The structure of the scale was examined by exploratory and confirmatory factor analyses. Internal consistency, test–retest reliability and concurrent validity were assessed. The final Partner-YW-BCI contained 36 items and assessed eight dimensions of the subjective experience of partners: (1) feeling of couple cohesion, (2) negative affectivity and apprehension about the future, (3) body image and sexuality, (4) career management, (5) deterioration of the relationships with close relatives, (6) management of child(ren) and of everyday life, (7) financial difficulties, and (8) sharing and support from close relatives. The scale showed adequate psychometric properties, and will help clinicians to identify the problems of partners and to respond to them by an optimal care management.