Background/Purpose: Currently, data on the real-world use of dronedarone, an antiarrhythmic drug for atrial fibrillation (AF), are contradictory and often based on patient populations comprised of Caucasians. We prospectively investigated the efficacy and safety of dronedarone and risk factors related to treatment outcomes in a real-world use setting. Methods: The prospective, observational, single-arm, multi-center study included a total of 824 Taiwanese patients with a diagnosis of paroxysmal or persistent AF and receiving dronedarone treatment. Risk factors analysis, efficacy, and safety of dronedarone were assessed with a follow-up of six months. Results: Of the 824 patients enrolled (mean age, 75.3 ± 7.2 years), 95.2% had at least one cardiovascular risk factor. An increase in the proportion of patients with sinus rhythm following treatment was seen (52.1% at baseline vs. 67.4% at 6 months). A decrease in the mean duration of AF episodes (388.4 min vs. 62.3 min) and an increase in total AFEQT (65.4 ± 16.2 vs. 74.0 ± 11.8) were also observed after 6 months of treatment. Females, those under the age of 75, and those with symptomatic AF had higher odds of treatment success. At 6 months, 10.5% of patients reported treatment-related AEs. However, only 0.2% of the AEs were both severe in nature and causally related to dronedarone. Conclusion: This six-month study showed dronedarone to be relatively safe and efficacious and to improve quality-of-life in Taiwanese patients with atrial fibrillation. Odds of treatment success were related to the patient's gender, age, and AF type.