Postoperative pulmonary complications are a common occurrence after major cardiac and thoracic surgeries because the effect of surgical procedures, anesthesia, and pain can impede chest wall movement and lung expansion. Aim: The aim of the present study was to determine the effect of nursing intervention on the reduction of pulmonary complications after thoracotomy. Design: A quasi-experimental research design was utilized in the study. Subject: A purposive sample of 70 adult patients from both genders required for thoracotomy was involved in this study and divided into two equal groups (35 patients in each group). Setting: This study was carried out at Surgical Intensive Care Units at National Heart Institute. Tools: Two tools were used for data collection (I) A structured interview assessment questionnaire, (II) Postoperative pulmonary complications assessment sheet. The results: This study revealed that, there was a statistically significant difference in the occurrence of postoperative pulmonary complications between the control and study group, in which the study group showed lower occurrence of postoperative pulmonary complications in comparison to the control group. Conclusion: Applying the nursing intervention by the researcher, which involves monitoring of hemodynamic and respiratory status, care of the chest tube, physiotherapy and deep breathing exercises, using incentive spirometer, early mobilization, sterile wound dressing, and control of pain help in reducing postoperative pulmonary complications as well as decrease the patient's length of stay in the hospital. Recommendations: This study recommended that; the designated nursing intervention should be carried out as a routine nursing care for the patients after thoracotomy.