The present study compares health-related QOL between patients who practiced self-care activities comprising exercise and diet at home for at least 6 months (SA group; n = 84) after elective PCI and those who did not (NA group; n = 54). Health-related (HR) QOL was measured using the SF-36 questionnaire. Scores for two mental and three physical parameters of the HRQOL were increased in the SA, but not in the NA group. These findings indicated that the QOL was far superior among patients who exercised and consumed an appropriate diet at home for at least 6 months after elective PCI compared with those who did not.