This study assessed the effects and safety of rivaroxaban versus warfarin in Chinese patients with atrial fibrillation. In this double-blind clinical trial, a total of 353 consecutive patients with atrial fibrillation who were at risk of stroke or systemic embolism were enrolled to receive either rivaroxaban or warfarin. The primary effect endpoint occurred in five patients in the rivaroxaban group (2.29% per year) and in seven patients in the warfarin group (2.91% per year) (hazard ratio with warfarin, 0.76, 95% CI, 0.64–0.91; p = 0.03). Major and non-major clinically relevant bleeding occurred in 38 patients (14.3% per year) in the rivaroxaban group and in 36 patients (13.7% per year) in the warfarin group (hazard ratio rivaroxaban versus warfarin, 1.07; 95% CI, 0.93–1.14; p = 0.39). Adverse events were similar between these two arms (p > 0.05). In conclusion, oral administration of rivaroxaban reduced the risk of stroke or systemic embolism without significantly increasing the safety concern.