Aim Current guidelines recommend administration of highdose statins in acute coronary syndrome (ACS). It has been reported that statins upregulate proprotein convertase subtilisin kexin 9 (PCSK9) mRNA expression and increase circulating PCSK9 levels. We aimed to compare the effects of high-dose atorvastatin and rosuvastatin on serum oxidized low-density lipoprotein (oxidized-LDL) and PCSK9 levels in statin-naive patients with ACS. Patients and methods One hundred and six patients with ACS were enrolled in this study. The patients were assigned randomly to receive atorvastatin (80 mg/day) or rosuvastatin (40 mg/day) by using a ratio of 1 : 1 in randomization. The levels of total cholesterol (TC), triglyceride, high-density lipoprotein cholesterol, LDLcholesterol, oxidized-LDL, and PCSK9 were compared between groups after a 4-week treatment. Results Our study population included 53 patients in the atorvastatin group (age: 58.13± 11.30 years, 11.32% female) and 53 patients in the rosuvastatin group (age: 59.08± 12.44 years, 15.09% female). In both groups, lipid parameters, oxidized-LDL, and PCSK9 values changed significantly according to the baseline following treatment. High-dose atorvastatin and rosuvastatin induced similar decreases in LDL-cholesterol, oxidized-LDL, and triglyceride levels and similarly increased in high-density lipoprotein cholesterol and PCSK9 levels (P>0.05). Conclusion We showed that atorvastatin and rosuvastatin treatment regimens have comparable effects on lipid parameters and PCSK9 levels in ACS patients.