In view of the higher prevalence of severe ischemic stroke among patients with atrial fibrillation (AF) and of the recently reported higher frequency of stroke with AF in females, 516 consecutive patients with ischemic stroke, of whom 93 had AF, were retrospectively evaluated. The main anamnestic, clinical and laboratory features of the AF and non-AF groups were statistically compared and the features of the AF group were statistically evaluated according to gender and age. Our results confirm the greater severity of stroke in AF patients than in non-AF patients and the higher frequency of stroke with AF in female patients. Moreover, a significantly higher frequency of stroke with AF was found in the male 60-69 and the female 80-89 age groups than in the other age groups. Relevant risk factors in females aged 80-89 were hypertension and left ventricular hypertrophy (LVH), while diabetes, alcohol, smoking and LVH prevailed among 60-69 year old males.