To assess coronary artery disease in arteriosclerosis obliterans (ASO), the efficacy of a dipyridamole-loaded ECG was evaluated. Subjects consisted of 35 patients who underwent surgery for ASO between November 1988 and December 1989. A dose of 0.568mg/kg of dipyridamole was intravenously infused for over 4min. Changes of systemic blood pressure, heart rate and standard 12-lead ECG were accumulated. In eleven cases loaded ECG was considered to be positive and coronary arteriographies were performed. Stenotic lesions of 75% or over were observed in 10 cases, among them CABG was performed in one symptomatic case. In another positive but asymptomatic cases, only the existing ASO lesions were surgically treated. No intraoperative or postoperative ECG abnormality was observed and postoperative courses were uneventful. Negative cases (24 cases) underwent complete revascularization. These findings indicate that a dipyridamole-loaded ECG is a non-invasive preoperative means detecting coronary artery disease preoperatively is useful to decide operative procedure.