Guidelines strongly recommend long-term anticoagulation with warfarin for patients with newly recognized AF who have high embolic risk by virtue of a CHADS₂ (Congestive Heart Failure, Hypertension, Age >65, Diabetes, History of Stroke) score ≥ 2.  The goal of this study was to determine patterns of emergency department-initiated anticoagulation among eligible patients discharged from Canadian centers with an episode of recent-onset atrial fibrillation and flutter (RAFF) and determine if decision-making is driven by the CHADS₂ score or other factors. This was accomplished by examining health records using uniform case identification and data abstraction as well as centralized quality control; it was conducted in 8 Canadian university emergency departments over a 12-month period. Eligible patients for this analysis demonstrated RAFF requiring emergency management, were not already taking warfarin and were not admitted to hospital. Univariate analyses were conducted using T-test or Chi-square to select factors associated with anticoagulation initiation at a significance level of p < 0.15 and multiple logistic regression was employed to evaluate independent predictors after adjustment for confounders. Among 633 eligible patients, only 21 out of 120 patients (18%) with a CHADS₂ score ≥ 2 received anticoagulation and among 70 patients who were given anticoagulation only 21 (30%) had a CHADS₂ score ≥ 2.  Independent predictors of anticoagulation included age by 10-year strata: (OR = 1.7; 95% CI 1.3 – 2.1), heparin use in the anticoagulation (OR = 9.6; 95% CI 4.9 – 18.9), a new prescription for metoprolol (OR = 9.6; 95% CI 4.9 – 18.9) and being referred to cardiology for follow-up (OR = 5.6; 95% CI 2.6 – 12.0).  CHADS₂ ≥ 2 doubled the likelihood of being prescribed anticoagulation (OR= 2.0; 95% CI 1.5 – 3.5) but was not an independent predictor.  It was thus determined that patients discharged from the emergency department in this study were not prescribed anticoagulation in keeping with current recommendations.  This practice gap merits further investigation and may benefit from educational efforts or enhanced support for anticoagulation use from the emergency department.