Introduction. Numerous studies suggest that total cholesterol content of erythrocyte membranes (CEM) might play a critical role in atherosclerotic plaque progression and instability. However, the exact role of CEM in atherosclerosis remains obscure. Our study was designed to investigate the association between CEM and the severity of coronary artery disease (CAD), and to assess the effect of rosuvastatin on CEM levels.Methods. CEM levels were assessed in 136 participants, including acute coronary syndrome (ACS) (non-ST-segment elevation ACS (NSTEACS) and ST-segment elevation myocardial infarction (STEMI)), stable angina pectoris (SAP), and controls. The Gensini score was used to estimate the severity of CAD. Additionally, 54 patients with CAD were medicated with rosuvastatin, 5 or 10 mg once daily, and then checked at 6 months.Results. The highest level of CEM was found in the STEMI group, followed by the NSTEACS, the SAP, and the control groups. Gensini score in group IV (CEM > 141.6 μg/mg) was markedly higher compared with group I (CEM ≤77.6 μg/mg). Gensini scores in group II (77.6 < CEM ≤111.1 μg/mg) and group III (111.1 < CEM ≤141.6 μg/mg) were also higher than in group I (all P < 0.001). Furthermore, a positive correlation was found between CEM levels and Gensini score (r = 0.714, P < 0.001). CEM levels were dose-dependently reduced by rosuvastatin therapy.Conclusions. CEM levels are positively associated with the severity of CAD, meaning that CEM might contribute to the development of CAD. Importantly, rosuvastatin could decrease CEM levels in patients with CAD and might effectively help to attenuate the progression of CAD.