PURPOSE: The purpose of this study was to identify relationships between quality of sleep, symptom cluster, depression, environmental disorder, and quality of life among hospitalized cancer patients. METHODS: The subjects were 114 patients who underwent chemotherapy for colon cancer, gastric cancer, gynecologic cancer and breast cancer. They were recruited from the cancer center of a university hospital. Data were collected from August 4th to 30th, 2011. The questionnaires included the Korean sleep scale A (quality of sleep), MDASI-K (symptom cluster), the environmental sleep disturbing scale, Zung's depression scale, and the Korean version of EORTC QLQ-C30. The collected data was analyzed by t-test, ANOVA, multiple regression analysis using the SPSS 19.0 program. RESULTS: Functional QOL was negatively associated with symptom QOL (r=-.798, p<.001). Symptom cluster, depression, & spouse (46.3%) were the most powerful predictors for functional QOL (46.3%) and symptom QOL (53.4%). CONCLUSION: It is evident that oncology nurses need to evaluate two dimensions of quality of life for cancer patients, for example, functional and symptom QOL. We recommend nurses develop specific protocols for relieving physical symptoms and alleviating depression, and furthermore test the effectiveness of them.