Background: Family health plays a vital role in the self-care and lifestyle modifications in families living with heart failure. Objective: To investigate the family health of patients with heart failure and their family members before and during the first COVID-19 lockdown. Method: This was a cross-sectional study design. We included 34 participants before and 34 participants during the first COVID-19 lockdown. Independent t-tests were conducted for comparison of the mean scores of the family health and its dimensions. Results: There was no significant difference between the total score of family health during the first COVID-19 lockdown compared to before the first COVID-19 lockdown in patients and family members. However, the values and ill-being dimensions of family health in patients and ill-being dimension in family members were significantly decreased during the first COVID-19 lockdown. Conclusion: This study indicated the positive and negative impacts of COVID-19 lockdown on family health. Implications for Nursing: Our results may help nurses to identify vulnerable patients with a low level of family health to tailor the best support to them.