The purpose of this study was to develope a critical pathway for the chemotherapy of non-small cell lung cancer patients and to identify its effects after implementation. Critical pathway was developed through 5 steps including content and clinical validity tests with collaborative efforts of nurses, clinicians, and other allied healthcare professionals with the aim of improving the quality of patient care, while minimizing cost to the patients. This paper was described an evaluation of the impact of a developed critical pathway on complication rate, length of stay, costs, the interval of treatment and patient satisfaction by nonequivalent control group posttest-only non-synchronized research design.Results were compared between the two groups of patients. There were no significant differences in demographic variables and the occurrence of bone marrow suppression between experimental group and control group(t=-0.01, p=0.992). There were statistically significant decreases in the average length of stay(t=-10.45, p=0.000), in the average cost(t=-2.988, p=0.004), and in the interval of treatment(t=-6.75, p=0.000) after implementation of the critical pathway compared to control group. Also, there was a statistically significant improvement of the patient satisfaction after implementation of the critical pathway compared to control group(t=4.57, p=0.000). This paper concludes that critical pathway in chemotherapy for lung cancer, implemented in the context of an general hospital, is the useful tool to shorten the hospital stay, reduce treatment costs, and improve the quality of life in cancer patients. Further study needs to be conducted to identify other clinical outcomes including job satisfaction, collaboration among health professionals and potential for use in education. Also, it is recommended that nurses should revise continuously the developed critical pathway through clinical implementation and maintain their role of patient advocacy through monitoring pathway compliance.