Background :The aim of this study was to validate whether pulmonary capillary wedge pressure estimated using transoesophageal echocardiography in anaesthetised patients receiving mechanical ventilation can be comparable to gold standard method of estimating PCWP by using pulmonary artery catheter. Methods : A cross sectional validity study conducted in a tertiary care cardiac centre in south India over a period of 6 months from February 2016 – August 2016 among 100 patients undergoing cardiac surgery where intraoperative TEE and pulmonary artery catheter used. In anesthetised patients, after the insertion of TEE probe, the following echocardiography ratios were calculated: 1) SF = S ⁄ S + D (systolic fraction of pulmonary venous flow 2) Systolic ⁄ diastolic (S ⁄ D ratio) 3) E ⁄ Ea 4) E ⁄ Vp 5) E ⁄ A ratio , for three consecutive cardiac cycles and averaged by two independent and blinded observers. All the echo measurements were taken pre cardiopulmonary bypass at end expiration and during a stable period of hemodynamics. Simultaneously PCWP was recorded from PAC. The ability of these variables to predict PCWP was tested for previously determined cutoffs as per extant guidelines and validity parameters such as sensitivity, specificity, predictive value of positives, predictive value of negatives & accuracy were computed. Conclusion : Use of E/A,DT,S/D,SF ratio & E/Vp reveal poor predictive capacity for detecting high left sided filling pressures. The use of E/Ea is reasonable to predict an elevated PCWP especially if the cohort predominantly comprises of patients with normal ejection fraction