Background: Fatigue is a common distressing problem in most cancer patients. It may be caused by the disease, the complications of the disease and its treatments. This study aimed to assess prevalence of fatigue and associated factors among adult cancer patients receiving various treatment. A cross sectional study was conducted on 278 patients from February 2019 to march 2019 in TASH Cancer Center. Brief Fatigue Inventory (BFI) scale was used for assessment of fatigue, other questions were concerning the socio-demographic data, medical condition and clinical factor included.rnObjectives: was to assess the prevalence of fatigue and associated factors among cancer patients February and March 2019, at TASH in Addis Ababa, Ethiopia.rnMethods: A cross-sectional study design was used among 278 randomly selected cancer patients undergoing cancer treatment at TASH. A standardized data collection tool, Brief Fatigue Inventory (BFI) was used to gather information from participants. The data was entered to EPI-data version 3.1 and transferred to SPSS version 24 for analysis. Bivariate and multivariable logistic regression were conducted to summarize the data. Level of confidence was determined at 95% CI and p-value