Purpose: The purpose of this study was to test a Winningham’s psychobiologic entropy model (PEM) on cancer related fatigue (CRF) among patients with solid tumors. Methods: Participants consisted of 213 patients with solid tumors recruited from December, 2012 through June, 2013, in a university hospital, in Hwasun, South Korea. Primary symptoms, adjustment, physical activity, status of nutrition and fatigue were measured using structured questionnaires. Collected data were analyzed using SPSS 21.0 and AMOS 21.0 programs. Results: The modifiedmodel tested provided a reasonable fit to the data (x2=65.80 [df=30, p<.001], TLI=.92, CFI=.95, RMSEA=.08, SRMR=.07). Primary symptoms (dyspnea, anxiety, depression and insomnia) had direct positive effects on CRF. Adjustment and status of nutrition showed indirect negative effects on CRF. However, the impact of physical activity was not significant. These variables explained 49.2% of the variance of CRF among solid tumor patients. Conclusion: The findings demonstrate that the tested model explain some CRF among solid tumor patients and warrant future research considering the cancer-related clinical factors of the given population.