Hepatocyte growth-promoting factor (pHGF) has the greatest potential as a therapeutic agent for vascular growth factor. The aim of this study was to investigate the effect of pHGF on myocardial ischemia and exercise capacity in patients with severe coronary artery disease (CAD). Forty-nine patients were enrolled for a two week treatment period. Treadmill graded exercise tests with gas analysis were conducted before and after therapy. Serum levels of HGF were significantly elevated after therapy. The degrees of exercise-induced ST segment depression were decreased more significantly in the pHGF group. Similar differences were also found in the maximum heart rate and the maximum heart rate when the ST segment was depressed 1 mm while undergoing the treadmill graded exercise test. Both were increased more significantly in the pHGF group. Total exercise time, systolic blood pressure in the peak of exercise, the length of time that ST segment depression of 1 mm is needed, and total work all were increased in both groups after intervention. Furthermore, total exercise time and total work were increased more significantly in the pHGF group. The levels of HGF increased significantly after pHGF treatment. pHGF could favorably improve exercise-induced myocardial ischemia and enhance exercise capacity in patients with severe CAD.