In the latest American Heart Association/American College of Cardiology/Heart Rhythm Society atrial fibrillation (AF) guidelines, CHA₂DS₂-VASc replaced the CHADS₂ stroke risk assessment to determine prophylactic anticoagulation, reflecting female gender's association with stroke incidence in AF. However, little investigation has been pursued of potential risk factors associated with worsened stroke severity. In this study, we examined patients with AF with ischemic stroke patient characteristics associated with increased stroke severity. Using the Get With The Guidelines-Stroke database, we retrospectively identified 221 consecutive patients with AF diagnosed with acute ischemic stroke and performed in depth chart review, evaluating demographics, labs, and co-morbidities. We analyzed the modified Rankin Scale (mRS) at discharge as a surrogate for stroke severity, defining severe stroke as fatal (mRS of 6) or disabling (mRS 4 to 5), requiring max assistance with ambulation or activities of daily living. Female gender, advanced age, and decreased body surface area were associated with disabling or fatal stroke (68.3% of patients with mRS 4 to 6 vs 50% with mRS 0 to 3, 78.4 vs 71.1 year, and 1.83 vs 1.92, respectively). Using a backward elimination approach revealed a logistic regression model with statistically significant odds ratios (ORs) for female gender (OR 1.99) and age (OR 1.04), and borderline significant for a history of coronary artery disease (OR 1.89). In conclusion, female gender is associated in the AF population with a twofold risk of severe disabling or fatal ischemic stroke, a finding that persists after controlling for potential confounders. This finding highlights the potential benefit from appropriate anticoagulation use for stroke prophylaxis in the AF population.