OBJECTIVE:To determine the 12-month cost-effectiveness of a collaborative care (CC) program for treating depression following coronary artery bypass graft (CABG) surgery versus physicians' usual care (UC). METHODS:We obtained 12 continuous months of Medicare and private medical insurance claims data on 189 patients who screened positive for depression following CABG surgery, met criteria for depression when reassessed by telephone 2 weeks following hospitalization (nine-item Patient Health Questionnaire ≥10) and were randomized to either an 8-month centralized, nurse-provided and telephone-delivered CC intervention for depression or to their physicians' UC. RESULTS:At 12 months following randomization, CC patients had $2068 lower but statistically similar estimated median costs compared to UC (P=.30) and a variety of sensitivity analyses produced no significant changes. The incremental cost-effectiveness ratio of CC was -$9889 (-$11,940 to -$7838) per additional quality-adjusted life-year (QALY), and there was 90% probability it would be cost-effective at the willingness to pay threshold of $20,000 per additional QALY. A bootstrapped cost-effectiveness plane also demonstrated a 68% probability of CC "dominating" UC (more QALYs at lower cost). CONCLUSIONS:Centralized, nurse-provided and telephone-delivered CC for post-CABG depression is a quality-improving and cost-effective treatment that meets generally accepted criteria for high-value care.