Background: The enlargement of the left atrium (LA) is thought to be a reflection of the long-term influence of left ventricular (LV) filling pressure against the LA. There is a correlation between increased LA volume and the risk of stroke and mortality. Objective: The aim of the current work was to determine the significance of LA size in stroke prognosis in patients of all ages who first presented with preserved left ventricular systolic function (LVSF) and sinus rhythm (SR). Patients and methods: This cross-sectional study included a total of 156 patients with acute ischemic stroke (AIS) with suspected symptom onset within the preceding 24 - 48 hours. Patients were divided into 2 groups, group I included 120 patients (76.9%) of cardio-embolic + large artery disease + small vessel disease patients and group II included 36 patients (23.1%) of cryptogenic and undetermined patients. Echocardiography was performed for all subjects. Results: Highly statistically significant (p-value < 0.001) increased LA volume index in group II patients (37.4 ± 3.9) when compared with group I patients (33.3 ± 6.2). Using Roc curve, it was shown that LA volume index can be used to discriminate between group I and group II at a cutoff value of > 37.5, with 52.8% sensitivity, 80.8% specificity, 73.3% PPV and 63.1% NPV (AUC = 0.69 & p-value = 0.0005). Conclusion: As a clinical tool, left atrial enlargement (LAE) may help determine the likelihood of a stroke and guide decisions about how to treat those who suffer from ischemic stroke.