In patients with non-valvular atrial fibrillation, warfarin anticoagulation is efficacious in stroke prevention. This meta-analysis aimed to clarify this benefit on prevention of ischemic stroke and vascular death against its risks of hemorrhagic stroke and major extracranial hemorrhages, and whether there is any difference between anticoagulation and anti platelet in stroke prevention. Randomised, clinical trials were included if they evaluated patients with nonvalvuvlar atrial fibrillation included a control group receiving a placebo or warfarin as standard treatment and aspirin as treatment being tested in evaluating reduction in stroke and vascular death for at least six weeks in duration. Ten trials were 5658 subjects were enrolled with non-valvular atrial fibrillation with mean follow-up of 2.5 years. Warfarin significantly reduced the risk of ischemic stroke and vascular death by). The over-all relative risk of stroke is 29% in the warfarin group and the relative risk reduction of ischemic stroke is 72% compared with placebo. There was no noted any greater benefit of reducing stroke and vascular deaths with anticoagulation than with antiplatelet treatment. Such findings conflict with previous findings of randomized controlled trials comparing anticoagulation with placebo. Recommended INR is 2 to 3. Warfarin is associated with risk of major bleeding. In patients with non-valvular atrial fibrillation, benefit is seen with warfarin in stroke prevention and vascular death. However, it was not superior to aspirin in reducing primary events. Target INR of2 to 3 confers protection for stroke and vascular death.