Increasing number of patients with advanced non-small cell lung cancer are receiving outpatient maintenance chemotherapy. It is very important to maintain these patients' quality of life(QOL). Pemetrexed has been reported to be an effective maintenance chemotherapy. However, its effects on the QOL of patients with non-small cell lung cancer who are undergoing outpatient maintenance chemotherapy are unknown; therefore, we conducted this study. To investigate factors that influence the QOL of these patients, we provided a QOL questionnaire,"The QOL Questionnaire for Cancer Patients Treated with Anticancer Drugs(QOL-ACD)"to 7 patients with non-small cell lung cancer. The medical factors related to the overall QOL scores, as well as other categories indicating"activity","physical condition","psychological condition","social relationship", and"face scale", were analyzed. No significant reductions in any of the factors were observed in this study.