Well-prepared informal caregivers play an important role in heart failure (HF) care, so an instrument to evaluate their preparedness to care is important. To date, HF caregiver preparedness has been rarely investigated quantitatively. The Caregiver Preparedness Scale (CPS) has been used in other chronic condition populations, but its psychometric characteristics have never been tested in HF caregivers. The purpose of this study was to test the validity and reliability of the 8-item CPS in HF caregivers. In a convenience sample of 317 HF caregivers (72.4% female, mean age 54), we tested the CPS' factorial structure with confirmatory factor analysis (CFA) and its concurrent validity with the Caregiver Contribution to Self-Care of HF Index (CC-SCHFI), and the Hospital Anxiety and Depression Scale (HADS). We also tested CPS' reliability with composite reliability indicators, Cronbach's alpha, factor score determinacy coefficient, and intraclass correlation coefficient (ICC). The CFA for a one-factor model resulted in supportive fit indices (e.g., comparative fit index .97). Significant correlations (p < .05) of the CPS with both the CC-SCHFI and the HADS supported concurrent validity. The composite reliability index, Cronbach's alpha, factor score determinacy coefficient, and ICC were .89, .91, .96, .91, respectively, supporting reliability. Our study provides evidence that the CPS is a valid and reliable instrument to measure HF caregiver preparedness, enabling clinicians, and researchers to target specific interventions to HF caregivers.