Background Stable coronary artery disease (CAD) is classified into 2 types: high-risk (ie, 3-vessel disease, left main trunk lesions, or ostial lesions of the left anterior descending (LAD)) and low-risk (1- or 2-vessel disease other than ostial lesions of the LAD), which comprise the majority of CAD patients. According to ACC/AHA/ACP-ASIM guidelines for low-risk CAD, anti-anginal agents should be initially administered to control attacks, then coronary intervention should be considered when medical therapy is not effective (medical-preceding therapy: M). In Japan, however, the initial treatment is generally percutaneous coronary intervention (PCI) combined with medical therapy (PCI-preceding therapy: P). Methods and Results In the present study the long-term outcomes of 190 M patients and 192 matched P patients at 34 nationwide hospitals were surveyed over 3 years (mean: 3.4 years) starting in 2000. Age, gender, initial severity of anginal symptoms, number of lesion vessels, risk factors and prescriptions were similar between the 2 groups. During the 3.4-year follow-up, additional PCI or coronary artery bypass grafting was required in 9.4% of the M group and in 33.2% of the P group. The rates of cardiac death were similar (1.6% in M and 2.6% in P). The overall rate of cardiac death and acute coronary syndrome was 2.1% in M and 4.7% in P, but the difference was not significant. The grade of anginal symptoms 12 months later was well improved in both M (1.6±1.4 to 0.6±0.9) and P (1.7±1.4 to 0.3±0.7) and there was no significant difference. Averaged annual medical cost was lower in M than in P (4.4-fold lower in the first year and 3.1-fold by the next year). Conclusions The present study suggests that M and P for Japanese low-risk CAD may have a similar effect on long-term prognosis, but M is cheaper. (Circ J 2006; 70: 365 - 369)