Major adverse cardio-cerebrovascular events (MACCE) in ST-segment elevation myocardial infarction (STEMI) are still high, although there have been advances in pharmacology and interventional procedures. Proprotein convertase subtilisin/Kexin type 9 (PCSK9) is a serine protease regulating lipid metabolism associated with inflammation in acute coronary syndrome. The MACCE is possibly related to polymorphisms in PCSK9. A prospective cohort observational study was designed to confirm the association between polymorphism of E670G and R46L in the PCSK9 gene with MACCE in STEMI. The Cox proportional hazards model and Spearman correlation were utilized in the study. The Genotyping of PCSK9 and ELISA was assayed.Sixty-five of 423 STEMI patients experienced MACCE in 6 months. The E670G polymorphism in PCSK9 was associated with MACCE (hazard ratio = 45.40; 95% confidence interval: 5.30–390.30; p = 0.00). There was a significant difference of PCSK9 plasma levels in patients with previous statin consumption (310 [220–1,220] pg/mL) versus those free of any statins (280 [190–1,520] pg/mL) (p = 0.001).E670G polymorphism of PCSK9 was associated with MACCE in STEMI within a 6-month follow-up. The plasma PCSK9 level was higher in statin users.