Introduction: Syncope in hypertrophic cardiomyopathy patients (HCM) is associated with high risk for sudden death, presence of fibrosis and LV structural changes. However, it is unclear if left atrial structural changes associate with syncope. Our aim is to evaluate changes in left atrial volume index (LAVI) and occurrence of syncope in HCM patients. Methods: Retrospective study of 123 HCM patients identified at our institution from 2016-2019. Syncope was identified by chart review of ICD codes, past medical history, and keyword search. Left atrial volume index was determined by tracing the LA endocardial border from standard views in two-dimensional echocardiography. HCM subtypes were classified as obstructive (oHCM) and non-obstructive (noHCM). Results: A total of 123 patients, 29 (23.6%) had syncope. No difference in age, gender, or BMI was found between those with syncope and without syncope. More ventricular arrhythmic events and stroke events occurred in those with syncope vs. without syncope. LAVI showed a correlation with syncope in HCM patients (p<0.05). Mean LAVI was larger in those with syncope compared to those without syncope (43.8±12.6 mL/m2 vs. 37.7±14.3 mL/m2). Each 1 mL/m2 increase in LAVI corresponded to a 1.03 OR risk for syncope. ROC analysis showed a LAVI threshold of 31.8mL/m2 for predicting syncope in all HCM (sensitivity 89.7%, specificity 40.4%) Conclusions: Syncope showed a strong correlation in those with larger LAVI with incremental risk of syncope for each 1 mL/m2 added to LAVI size. Additionally HCM patients with syncope had worse outcomes. Our findings suggest LAVI may have utility as a marker to stratify HCM patients at risk for syncope. Further studies in HCM patients are needed to assess the impact of changes in LAVI size over time on cardiovascular outcomes.