Background: Chronic aortic regurgitation (AR) is a form of volume overload inducing left ventricle (LV) dilatation. Myocardial fibrosis, apoptosis, progressive LV dilatation, and eventually LV dysfunction are seen with the progression of disease. The aim of the study was to assess the relation between LV geometry and LV systolic and diastolic functions in patients with chronic severe AR. Methods: The study population consisted of 88 patients with chronic severe AR and 42 healthy controls. The LV ejection fraction (LVEF) was calculated. Subjects were divided as Group I (controls, n = 42), Group II (LVEF > 50%, n = 47), and Group III (LVEF < 50%, n = 41). Transmitral early and late diastolic velocities and deceleration time were measured. The annular systolic (Sa) and diastolic (Ea and Aa) velocities were recorded. Diastolic function was classified as normal, impaired relaxation (IR), pseudonormalization (PN), and restrictive pattern (RP). Results: The LVEF was similar in Group I and II, while significantly lower in Group III. Sa velocity was progressively decreasing, but LV long- and short-axis diameters were increasing from Group I to Group III. Forty-six, 31 and 11 patients had IR, PN, and RP, respectively. LV long-axis systolic and diastolic diameters were significantly increasing, while LVEF and Sa velocity were significantly decreasing from patients with IR to patients with RP. The LV long-axis diastolic diameter is independently associated with LV systolic and diastolic functions. Conclusions: The LV long-axis diastolic diameter is closely related with LV systolic and diastolic functions in patients with chronic severe AR.