Background: Cancer related fatigue, depression and functional dependence are among a confusing array of symptoms which commonly presented in the patients undergoing cancer treatment. These symptoms especially fatigue still largely ignored in older adults, hence, identifying these symptoms and analyzing the correlation which can be exist may have a special concern and are considering important cues for effective management of these symptoms. Aim: To determine the relation of cancer related fatigue with depression and functional status among elderly patients undergoing radiotherapy. Method: This is a descriptive correlational study designcarried on 120 elderly cancer patients that were attending the outpatient of the Oncology Department, Enam Medical College & Hospital, Dhaka, Bangladesh and were undergoing radiotherapy, patients were interviewed individually by the researcher to collect data using the study tools; Tool-I: Interview questionnaire sheet, Tool-II: Revised Piper Fatigue Scale, Tool-III: Geriatric Depression Scale –short form, Tool-IV: Katz and Akpom scale, and Tool-V: Lawton and Brody scale. Results: Fatigue was positively correlated with depression and Katz scale for activity of daily livings; the higher fatigue was associated with higher depression and lower independency level. Also, there was a positive moderate correlation between depression and functional dependence in anactivity of daily livings. Conclusion: Fatigue, depression, and functional dependence are commonly and correlated symptoms in elderly cancer patients undergoing radiotherapy.