Major depressive disorders complicate recovery from acute coronary syndrome in approximately 1 in 5 patients, and have been found to be associated with significant impairments of quality of life and functioning. The aim of the present analysis was to evaluate the efficacy of sertraline in improving quality of life and functioning in patients diagnosed with major depression who had recently been hospitalized for acute coronary syndrome. Three hundred sixty-nine patients hospitalized in the previous month for acute coronary syndrome (myocardial infarction, 74%; unstable angina, 26%) who also met criteria for major depressive disorder were randomized to 24 weeks of double-blind treatment with sertraline (50 to 200 mg/day) or placebo. Quality-of-life and functional status were assessed using the Quality of Life, Enjoyment, and Satisfaction scale (Q-LES-Q) and the Medical Outcomes Study SF-36. Data from the total sample, and the recurrent depression subgroup, were analyzed. Severe baseline impairment was found in the Q-LES-Q and all subscales of the SF-36. A multivariate regression analysis identified depression as the strongest predictor of baseline quality-of-life impairment (partial r, -0.37, p = 0.001). In the recurrent depression group, treatment with sertraline resulted in significantly greater improvement than placebo in the Q-LES-Q total score and SF-36 mental component summary score, as well as the SF-36 role limitations, emotional, and mental health factors. Depression has a substantial negative impact on quality of life and functioning in patients hospitalized for acute coronary syndrome. Sertraline was associated with clinically meaningful improvement in multiple quality-of-life domains in patients with acute coronary syndrome and recurrent depression.