Background: The Heart Failure Caregiver Questionnaire (HF-CQ®) was developed to assess subjective outcomes of heart failure caregivers. The HF-CQ® comprises 21 questions on three domains, namely physical, emotional/psychological and lifestyle. The objective of this study was to evaluate the psychometric properties of the HF-CQ®. Methods: Patients (n = 150) with heart failure and their primary caregivers (n = 150) were recruited from 11 sites in USA. Caregivers completed the HF-CQ® and additional questionnaires, namely Caregiver Reaction Assessment, Work Productivity and Activity Impairment questionnaire, EuroQol-5 domain, and the Hospital Anxiety and Depression Scale. Patient-completed Global Impression of Severity, construct validity, concurrent validity, reliability and responsiveness of the HF-CQ® were also assessed. Results: In the physical and lifestyle domains, all items showed acceptable validity. No high correlations between HF-CQ® scores and other caregiver-completed instruments, including the Hospital Anxiety and Depression Scale, Work Productivity and Activity Impairment questionnaire, EuroQol-5 domain or Caregiver Reaction Assessment, were reported. The intra-class correlation coefficient exceeded the threshold for reliability (>0.7) across the physical well-being (0.785), emotional/psychological (0.797), lifestyle (0.787) and total scores (0.850), indicating acceptable reliability. Internal consistency results using Cronbach’s alpha showed the total aggregate score of 0.942 to be reliable. In the responsiveness analyses, each of the three scales and the total score showed responsiveness to changes defined by the Caregiver Global Impression of Severity. The overall caregiver burden score increased with increased severity of illness in the cared-for patients. Conclusions: The study provides initial evidence for the acceptable validity of the HF-CQ® as an instrument to measure heart failure caregiver burden.