Purpose: This is develop a critical pathway as an useful alternative to the previous management system in order to restriction of medical resources, high expectation of ordinary people to health and application for DRG. Method: In order to preliminary critical pathway, we analyzed 30 cases of medical records of patients who had lobectomy and pneumonectomy at the Yonsei Medical Center in Seoul. An expert validity test was taken for the preliminary critical pathway, and clinical validity test was also done. After these processes, the final critical pathway was developed. Result: Among 10 cases, one was excluded in this study due to the complication after operation. 7 of total 9 patients were discharged earlier than the expected day, 1 patient was just discharged at the expected day, and 1 patient was discharged 4 days later than the expected day at the 12th day after operation. Conclusion: The critical pathway is developed without difficulty because the posoperative management for patients with lobectomy and pneumonectomy is uncomplicated. Therefore, if it is more researched on the clinical application, then the activity of C.Q.I. will be able to sustain the patient oriented management system.