Objective: Thoracic epidural anesthesia and analgesia remains a preferred technique for the perioperative period of thoracic surgery.The current thesis aimed to compare the effect of thoracic epidural ropivacaine versus thoracic epidural fentanyl on the incidence of right ventricular dysfunction and postoperative arrhythmia following lung resection using one lung ventilation, and to compare the effect of each drug on the postoperative pulmonary functions.Design: Double – blind prospective comparative study.Setting: Cairo University hospital cardiothoracic operative theater.Participants: Thirty patients of both sexes undergoing lung resection surgery were included in the study.Methods: Patients were divided into two groups (15 patients each); group R received ropivacaine thoracic epidural infusion and group F received fentanyl thoracic epidural infusion. The patients underwent lung resections using one lung ventilation and transesophgeal echocardiography were used to assess pulmonary hemodynamics and right ventricular function during the procedure. All patients were monitored postoperative for occurrence of cardiac dysrrhythmia, Pulmonary function tests were performed for all the patients including assessment of FEV1 & FVC one day before operation as baseline and postoperatively.Results: The results showed that the use of thoracic epidural ropivacaine and thoracic epidural fentanyl had no significant difference regarding the effect on perioperative hemodynamics, the right ventricular functions and pulmonary hemodynamic during the procedure.Pulmonary functions tests postoperatively were preserved more in the ropivacaine group than the fentanyl group and there was a statistically significant difference between the two groups.The incidence of postoperative dysrrythmias was lower in the ropivacaine group than the fentanyl group. Conclusion: Patients who received thoracic epidural ropivacaine showed better preservation of pulmonary functions than patients with thoracic epidural fentanyl, and less incidence of perioperative dysrrthmias.