This study aimed to evaluate the effectiveness of treating dyslipidemia with a combination of rosuvastatin and ezetimibe in patients with chronic coronary artery disease compared to rosuvastatin 20 mg monotherapy in Vietnam. Materials and M ethods: This was a randomized controlled clinical trial with a 1:1 single-blind distribution involving 102 patients with chronic coronary syndromes. The intervention group received combined treatment with rosuvastatin 10 mg plus ezetimibe 10 mg daily, while the control group received rosuvastatin 20 mg daily. The primary outcome was the efficacy of LDL-C control between the two groups after 4 and 8 weeks. Results: The average concentration of LDL-C before intervention, after 4 weeks, and after 8 weeks in the intervention group was 2,84 mmol/L, 1,43 mmol/L, and 1,18 mmol/L, respectively. In the control group, the average concentrations were 2,39 mmol/L, 1,68 mmol/L, and 1,41 mmol/L (p=0,001). After 8 weeks of intervention, the LDL-C ratio <1,4 mmol/L in the intervention and control groups was 41.2% and 74.8%, respectively (PR=1,8, p=0,0007).The rate of reaching the 50% LDL-C reduction goal was 60,8% and 23,5% (RR=2,6, p=0,001), and achieving both goals was 57% and 21% (RR=2,6, p=0,0003). The combination regimen showed fewer side effects than the increased dose monotherapy, and both regimens were safe for patients. Conclusion: The combination of rosuvastatin lOmg and ezetimibe lOmg was more effective in reducing LDL-C levels and achieving treatment goals than rosuvastatin 20mg monotherapy. This combination regimen was also safer and had fewer side effects.