Lung cancer is the number one cause of cancer death in Taiwan, as in much of the industrialized world, yet studies describing the experience of patients living with lung cancer are limited. Sleep disturbance has been reported as a health problem in lung cancer patients. Poor sleeping quality results in a decline of the functional status of health. Although there have been many studies related to sleep measures and assessment, little attention has been paid to the incidence and severity of sleep quality and their impact on lung cancer patients, especially in Taiwan. The purpose of this study was (1) to investigate prevalence of sleep disturbance in patients with advanced non-small cell lung cancer; (2) to analyze the predictors of sleep quality. A cross-sectional research design was utilized for this study, including 204 samples. Measurements included demographic and disease characteristic sheets, M.D. Anderson Symptom Inventory Taiwan Form, and Chinese Version Pittsburgh Sleep Quality Index (CPSQI). Statistical analyses included descriptive statistics, Pearson's correlation, t-test, ANOVA, and multiple regression analysis. The average global score of the CPSQI was 10.20 which indicated poor sleep in patients with lung cancer. 78% patients in this study have had sleep disturbance. The relationships between educational level, working status, and Karnfsky and CPSQI scores were significant. Karnofsky scores can serve as predictor in sleep quality. Results from this study can provide an important basis for possible development of new strategies to manage sleep disturbance in non-small lung cancer patients which may have a great potential to improve the quality of sleep for patients with non-small cell lung cancer.