In 76 patients (66 men and 10 women, age 20-71 years) with stable angina pectoris planar thallium myocardial perfusion scintigraphy, bicycle ergometry and coronary angiography were performed. Thallium scintigraphy was highly sensitive (97%) for detection of ischaemic heart disease, the sensitivity of ergometry was 75%. When comparing patients with affected 1, 2 and 3 coronary arteries perfusion scintigraphy had a sensitivity of 100%, 90% and 100% resp., while bicycle ergometry 62%, 90% and 82% resp. The specificity of perfusion scintigraphy was low (47%), compared with ergometry (60%). The finding of s reversible perfusion defect during scintigraphy indicated significant affection of coronary arteries. The scintigraphic finding of diffuse myocardial ischaemic affection was not significant for assessment of the severity of the coronary artery disease.