Left ventricular (LV) hypertrophy (LVH) is a known independent determinant of left atrial (LA) size; however, there is controversy regarding whether the LV geometric patterns are associated with LA enlargement (LAE), a major indicator of diastolic heart failure. The authors evaluated 47,865 patients with preserved ejection fraction to determine the relationship of LV geometry on LAE as determined by LA volume index (LAVi) 29 mL⁄m². Abnormal LV geometry was identified in 48% and LAE was indentified in 43% with associated higher prevalence of abnormal LV geometry(59% vs 41%, P<.0001). Both LV mass index and relative wall thickness (RWT) were independent determinants of LAE (P<.0001). LAVi and prevalence of LAE differ significantly by LV geometric patterns (P<.0001). In multivariate analysis, abnormal LV geometry patterns, especially eccentric and concentric LVH, were independently associated with LAE. In conclusion, LAE assessed as increased LAVi is strongly associated not only with LV mass index but also with RWT. Furthermore, LAE was independently associated with abnormalities in LV geometry.