We compared three techniques of aortic valve area (AVA) measurement using transesophageal echocardiography (TEE) and determined if AVA can be predicted from simple patient or echocardiographic measurements. AVA was simultaneously measured with direct planimetry, the continuity equation and with a novel technique combining stroke volume using thermodilution and continuous wave Doppler. Using planimetry as the reference in patients with normal valves, left ventricular outflow tract area (LVOTA), lean body mass (LBM), body surface area (BSA) and height were assessed as predictors of AVA. All three methods of AVA measurement showed close agreement and can be used interchangeably. Both LVOTA and LBM were predictors of AVA, but LVOTA was better. BSA and height were not acceptable as predictors of AVA. TEE can be used to measure AVA either with planimetry, the continuity equation, or in combination with thermodilution. LVOTA was the best predictor of AVA.