This study compared the diagnostic accuracy of dipyridamole (0.84 mg i.v./ 10 min) and bicycle stress echocardiography in 37 patients with inconclusive standard bicycle electrocardiography (ECG) tests; all underwent coronary angiography. Sensitivity for detection of coronary stenosis with dipyridamole echocardiography was 68% (21 of 31 patients), and for 1-, 2- and 3-vessel disease 56, 69 and 83%, respectively. Overall bicycle echocardiography sensitivity was 84%, and 78, 88 and 83% for patients with 1-, 2- and 3-vessel disease, respectively. Dipyridamole echocardiography was negative in all 6 patients with negative coronary angiography (specificity 100%), bicycle echocardiography was positive in 2 (specificity 67%). We conclude that dipyridamole echocardiography tends to be less sensitive in patients with mild disease, but is more specific than bicycle echocardiography.