Background: Caregivers make an important contribution to the self-care of patients with heart failure (HF), but few instruments are available to measure this contribution. Objective: The objective of this study was to test the psychometric properties of the Caregiver Contribution to Self-care of Heart Failure Index (CC-SCHFI), an instrument derived from the Self-care of Heart Failure Index version 6.2. The CC-SCHFI measures the contribution of caregivers to the self-care maintenance and self-care management of HF patients, as well as their confidence in their ability to contribute to the patients’ HF self-care. Methods: A cross-sectional design was used to study 291 Italian caregivers whose HF patients were cared for in 17 cardiovascular centers across Italy. Caregivers completed the CC-SCHFI and a sociodemographic questionnaire. Caregivers were retested on the CC-SCHFI 2 weeks later to assess test-retest reliability. Results: Most caregivers were women (66%) with a mean age of 59 years. First- and second-order confirmatory factor analysis (CFA) for each CC-SCHFI scale showed good model fit: χ 2 = 37.22, P = .08, Comparative Fit Index (CFI) = 0.97, Non-Normed Fit Index (NNFI) = 0.96 for caregiver contribution to self-care maintenance (second-order CFA); χ 2 = 14.05, P = .12, CFI = 0.96, NNFI = 0.93 for caregiver contribution to self-care management (first-order CFA); and χ 2 = 10.63, P = .15, CFI = 0.99, NNFI = 0.98 for caregiver confidence in contributing to self-care (second-order CFA). The CC-SCHFI was able to discriminate statistical and clinical differences between 2 groups of caregivers who had received or not received HF self-care education. Internal consistency reliability measured by factor score determinacy was more than .80 for all factors and scales except for 1 factor in the caregiver contribution to self-care management scale (.65). Test-retest reliability computed by intraclass correlation coefficient was high (>0.90) for most factors and scales. Conclusion: The CC-SCHFI showed good psychometric properties of validity and reliability and can be used to measure the contribution of caregiver to HF patient self-care.