We retrospectively compared the cost-benefit ratio of coronary bypass grafting (CABG) and percutaneous coronary angioplasty (PTCA). Data were obtained on 40 CABG's and 40 PTCA's patients treated from 15/2/86 to 15/9/86. All patients had at last 1-year follow-up. PTCA and CABG groups had similar baseline clinical and angiographic criteria. We analyzed the following cost components: real estate, biomedical products, drugs, hospital charges, medical fees, cardiac and non-cardiac tests. Total cost of CABG exceeds that of PTCA by a factor of 1.64: 15,095,000 vs 9,201,346 Italian liras (ILit). Taking into account early and late medical and surgical complications, the factor decreases to 1.39: 15,746,500 vs 11,323,000 ILit. After 1 year of follow-up the factor decreases to 1.18: 16,613,500 vs 14,027,500 ILit. Our data show that the initial savings were reduced when complications and follow-up are considered, but PTCA's patients had shorter hospitalization, earlier return to work, lower psychosocial stress.