Objectives. This study was performed to assess the quality of life of patients with left ventricular dysfunction for up to 2 years after randomization to enalapril or placebo. Background. Previous reports have documented that survival of patients with congestive heart failure can be extended by the angiotensin-converting enzyme inhibitor enalapril. However, it is unknown whether enalapril has a long-term favorable impact on the quality of life in patients with heart failure. Methods. A brief quality of life questionnaire assessing the quality of life was administered at baseline and at 6 weeks, 1 year and 2 years of follow-up to patients randomized to placebo or enalapril in the Studies of Left Ventricular Dysfunction (SOLVD). Participants had an ejection fraction ≤ 0.35, no other serious illnesses and either symptomatic heart failure (treatment trial, n = 2,465) or asymptomatic left ventricular dysfunction (prevention trial, n = 2,560). Results. Among the 14 scales of quality of life, better scores at one or more follow-up intervals were noted in 6 scales in the treatment trial and in 1 scale in the prevention trial among patients assigned to enalapril. Consistent superiority with enalapril at two consecutive follow-up intervals was noted in the treatment trial for social functioning and dyspnea but for no scale in the prevention trial. However, an average of 40% of quality of life responses were missing at 2 years of follow-up because of death or failure to complete the questionnaire. In the treatment trial, survivors with more severe heart failure were less likely to complete the questionnaire. Conclusions. Modest benefits in quality of life for ≥ 1 year occurred when patients with left ventricular dysfunction and symptomatic heart failure were treated with enalapril. No apparent beneficial or adverse effect on quality of life was observed with enalapril in asymptomatic patients with left ventricular dysfunction. © 1994.