A 57-year-old male with a previous history of inferior myocardial infarction suffered from chest pain and diagnosed as ST-segment elevation myocardial infarction (STEMI). Coronary angiography revealed a thrombus with delayed filling in the distal right coronary artery. After an aspiration thrombectomy, TIMI 3 flow was restored successfully. An intracoronary ultrasound imaging revealed coronary ectasia. Stenting and ballooning were deferred. A successful lone aspiration thrombectomy was performed for a patient with STEMI associated with coronary ectasia.