Direct percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) is now established as a standard therapy for older patients. However, experience with PCI in very young adults with AMI has been limited. In this report we retrospectively evaluated the effectiveness of PCI for very young adults with AMI and estimated their clinical characteristics and outcome. Of the 502 patients with AMI, 5 were 35 years old or younger (1.0%) during a period of 4 years (2000--2004). We assessed the utility of PCI in these five consecutive patients under the age of 35 presenting with a first AMI. Five AMI patients, ranging in age from 20 to 34 years (median, 27+/-5 years) underwent direct PCI for the culprit lesions. The lesions targeted for PCI were located in the left anterior descending artery in 3 patients and in the right coronary artery in 2 patients. One patient had a past history of Kawasaki disease (KD). In all of the patients, PCI were angiographically effective at the acute phase without complication. In hospital course, a subacute stent thrombosis occurred in one patient. Follow-up angiograms performed 6 months after the procedure revealed no restenosis, but identified a new coronary aneurysm in one patient with a past history of KD and a regressed giant coronary aneurysm probably due to atypical KD in another patient, which were confirmed by intravascular ultrasound. There was one death ascribed to heart failure 8 months after the initial PCI. The findings of this report suggest that PCI for very young adults with AMI can be safe and effective in the short-term.