Background— Prior comparisons of costs following CABG and PTCA have demonstrated higher initial costs after CABG but following PTCA, recurrent symptoms and repeat revascularization result in increased late costs and over time their costs equilibrate. The MASS II trial provides an opportunity to compare the costs of CABG and PTCA in addition to a strategy of medical therapy. Methods— We studied the 611 patients of MASS II [Medical (203), Angioplasty (205), or Surgery (203) Study], a randomized study to compare treatments for multivessel CAD and preserved left ventricle function. The costs were: CABG US$ 10 650.00; PTCA US$ 6400.00; new AMI hospitalization AMI U$ 2550; angiography not followed-up of PTCA US$ 1900.00; and medication US$ 1200.00 for medical, and US$ 1000.00 for the other groups. We did adjustment for average event-free time, and angina-free proportion. The statistical analysis carried out was chi-square, t test, and analysis of variance. Results— After 1 year, 49% Medical, 79% PTCA, and 88% CABG became angina-free; P <0.0001. There were 26 coronary angiograms (5 medical, 17 PTCA, and 4 CABG), 23 AMI (8 medical, 17 PTCA, and 6 CABG; P =0.03); PTCA was performed in 7 Medical, 17 PTCA, and 1 CABG, ( P =0.0003), CABG was performed in 15 Medical, 8 PTCA, and zero CABG; P =0.002. The event-free and event and angina-free-costs in the first year were US$ 2453.50 and US$5006.32 for Medical; US$ 10348,43; and US$ 13 099.31 for PTCA; and US$ 12 404.21 and US$ 14 095.09 for CABG group. An increase from expected costs of 317%, 77%, and 21%, respectively. Conclusion— PTCA effective costs were similar to CAGB costs, Medical treatment presented the lowest cost, and however, the greatest increment, and CABG presented the most stable costs.