Purpose: This study was conducted to identify comprehensive predictors of fatigue in cancer patients. Methods: One hundred ten cancer patients visiting in-patient or out-patient clinics of a university hospital located in Incheon participated in this study. Results: The hematologic indicators (WBC and Hemoglobin) were significant fo. explaining fatigue. The psychological factors of fatigue were statistically significant. Both anxiety and depression, included as psychological factors, were significant in explaining fatigue in cancer patients. The influence of physical factors on fatigue was also statistically significant. Among the variables included as physical factors, pain, nausea/vomiting/anorexia, and sleep disturbance were significant whereas, dyspnea was not significant. The influence of the daily activity factor on fatigue was statistically significant. Among the variables included as daily activity factors, regular exercise or not and the usual activity level were significant in explaining fatigue of cancer patients, while the level of rest was not statistically significant. Conclusions: From the study results fatigue of cancer patients appeared to be influenced by multidimensional factors, such as physiological, physical, psychological, and activity related factors.