Cancer is a term used to describe a group of diseases characterized by the uncontrollable growth and spread of aberrant cells. Cancer treatment requires multimodality approach such as surgery, radiation therapy, chemotherapy, immunotherapy and targeted therapy etc. Radiation therapy (also called radiotherapy) is a cancer treatment that uses high doses of radiation to kill cancer cells and shrink tumors. When it comes to cancer patients, fatigue is one of the most commonly recognized symptoms in the literature, as well as one of the most common adverse effects of radiation therapy. Radiation-induced fatigue (RIF) is a clinical subtype of cancer-related fatigue (CRF) that occurs during radiation therapy (acute RIF) or persists later, according to the National Comprehensive Cancer Network (NCCN) (chronic RIF). Radiation induced fatigue (RIF) is a severe, persistent, and subjective feeling of physical, emotional, or cognitive fatigue. In this study, we aimed to evaluate the extent of fatigue among cancer patients receiving radiation therapy at the Department of Radiation Oncology in Sri Venkateswara Institute of Medical Sciences, a South Indian tertiary care teaching hospital in Tirupati, Andhra Pradesh. A prospective observational study was conducted, and data was collected from the patients using fatigue scale questionnaire, Multidimensional Fatigue Inventory (MIF).