Aortocoronary dissection and coronary perforation are rare complications of percutaneous coronary intervention (PCI). We present a 68-year-old man with aortocoronary dissection involving the right coronary artery (RCA) and ascending aorta during PCI. We tried to seal off the entry site by using conventional stenting but failed. After reviewing angiograms, a subtle leakage of contrast into the pericardial space before stenting led us to the diagnosis of coronary perforation. Finally, we successfully treated this complication by deploying a covered stent. This case report reminds us that coronary perforation could be missed if there is only subtle contrast jet in the angiogram. Prompt treatment with conventional stenting may be harmful for coronary perforation. Detailed review of angiograms before management of coronary dissection is mandatory.