Abstract: AIM To evaluate the effect of rosuvastatin on paroxysmal atrial fibrillation (PAF) in patients with dilated cardiomyopathy (DCM) after cardiac resynchronization therapy (CRT) and to explore its mechanism. METHODS Forty-four DCM patients who had undergone CRT were randomly divided into rosuvastatin group (22 patients) and control group (22 patients). Echocardiographic data, LDL-C, BNP and CRP were detected at the beginning of the study and 18 months after. Atrial fibrillations recorded by pacemakers were analyzed. RESULTS At baseline, no significant differences were found between groups (P>0.05). But 18 months after, CRP, BNP, LAD and LVEDD were significantly reduced in rosuvastatin group (P<0.05, P<0.01) and only BNP and LVEDD were reduced significantly in control group (P<0.05). LVEF increased significantly in both groups (P<0.05) and LDL-C reduced in both groups, but with no statistically significant difference (P>0.05). Ten of the 42 (23.8%) patients had new AF during follow up, with no statistically significant difference in rosuvastatin group (2/21, P>0.05), but with significant increase in the control group (8/21, P<0.05). CONCLUSION Rosuvastatin can reduce the risk of PAF in patients with DCM after cardiac resynchronization therapy possibly by the anti-inflammatory effects of rosuvastatin independently of its lipid-lowering role.