The purpose of this study was to determine the rate of participation of patients after acute myocardial infarction (AMI) in phase II cardiac rehabilitation with exercise training (ie, exercise cardiac rehabilitation, ECR) in Japan. Forty-six hospitals treating patients with AMI were surveyed for their implementation of phase II ECR after AMI in 1996-98. Of the 46 hospitals, 19 were approved and 27 were not approved for health insurance payment for ECR. A total of 13685 patients with AMI were admitted to the 46 hospitals. There were no differences between approved and non-approved hospitals in the annual number of patients with AMI (Approved, 117+61 vs Non-approved, 86+71 patients per hospital, NS), the rate of performance of emergency coronary angioplasty (63+16 vs 65+20%, NS), or the rate of emergency coronary stenting (31+16 vs 34+22%, NS). However, ECR was performed routinely in 84.2% (16/19 hospitals) of the approved hospitals, but in only 22.2% (6/27 hospitals) of the non-approved hospitals (p<0.001). Although the participation rate of AMI patients in ECR was 21.0% (2875/13685 patients) overall, it was markedly lower in the non-approved hospitals (8.0%, 557/6999 patients) than in the approved hospitals (34.7%, 2318/6686 patients, p<0.0001). Based on the present result, the overall rate of participation of AMI patients in ECR in Japan was estimated at 4.8-11.7%. Despite similar patient volumes and acute phase interventional treatment of AMI between the hospitals approved and not approved for health insurance payment for ECR, ECR was markedly underused in the non-approved hospitals in Japan. To promote ECR for all AMI patients in Japan, the number of hospitals approved for ECR should be substantially increased.