The door-to-balloon time and total ischemic time are important predictors of the outcome in patients with ST elevation myocardial infarction (STEMI) receiving primary angioplasty, but the current situation in Japan is unknown. The Japan Acute Myocardial Infarction registry is a prospective observational study of 2,030 consecutive STEMI patients admitted to 213 Japanese institutions. The time from symptom onset to hospital arrival, door-to-balloon time, and in-hospital outcome were assessed. Data were compared between patients treated during regular hours or after hours. Percutaneous coronary angioplasty was done in 97.2 % of the patients, using drug-eluting stents in 30 % and bare metal stents in 63 % of the treated cases. The median symptom onset-to-door time (25th and 75th percentiles) was 135 min (64-305 min), median door-to-balloon time was 42 min (28-66 min), and mean procedural time was 98 ± 51 min. The on-call catheterization team performed 48.5 % of the procedures. There was no significant difference of door-to-balloon time between the patients treated after hours and those treated during regular hours. The cardiac mortality rate was 3.2 %, and it increased with longer door-to-balloon times (P = 0.03). The relationship between total ischemic time and cardiac mortality showed 2 peaks, with a trough at 5 h. Median door-to-balloon time was <90 min and was not longer in after hours cases. These findings suggest that Japanese institutions can provide primary angioplasty within an acceptable time frame.