Objective: Develop and validate an instrument to assess family resilience and, more specifically, the family dynamics and resources, estimating the adaptation flexibility to cancer disease. Cohesion, communication, coping style and relational style were considered as critical functional areas in the construction of the instrument.; Design: Two cross-sectional studies. Study 1: identification of factorial structure of the questionnaire in two samples with different cancer sites. Study 2: validation of the questionnaire in patients with cancer in two different phases of their therapeutic pathway.; Participants and Setting: A total of 213 patients with a histologically confirmed non-metastatic breast or prostate cancer and 209 caregivers were recruited for the two studies from an oncological hospital in Italy.; Outcome Measures: The Resilience Scale for Adults and the Family Resilience (FaRE) Questionnaire, developed by the researchers, were administered to all patients and caregivers who gave consent.; Results: In study 1, the 60-item version of the FaRE Questionnaire underwent discriminant and construct validity, internal consistency and factorial analysis. Comparisons between patient and caregiver populations showed that patients perceived higher levels of family resources (p=0.048) and that patients with prostate cancer perceived less social support compared with patients with breast cancer (p=0.002). Factor analysis demonstrated four domains: communication and cohesion, perceived social support, perceived family coping, and religiousness and spirituality. In study 2, the validity and factorial structure of the final scale, composed of 24 items, were confirmed. The Cronbach alpha of all subscales was above 82. Normative values for patients with breast cancer can provide indications of family resilience levels.; Conclusions: Preliminary findings showed acceptable psychometric properties for the FaRE Questionnaire to evaluate family resilience in oncological patients and their caregivers. Further research should test its sensibility to change to assess its use as a psychoemotional monitoring tool and its validity in other medical contexts.