Background: Radiation therapy is an important treatment modality of cancer therapy. Especially for Breast Cancer it stands as primary approach of the treatment along with chemotherapy. However, radiation therapy is associated with certain adverse events which may cause significant discomfort to patients and may impact on their day-to-day activities. The objective of the study is to study the pattern of radiation related adverse events and their management in patients who are on radiation therapy or chemo-radiation therapy in breast cancer. Materials and Methods: A prospective observational study was conducted over one year at Bharath Hospital and Institute of Oncology, Mysore, following ethical approval from the Institutional Ethics Committee. The study evaluated radiation-induced adverse events in breast cancer patients using MedDRA codes and RTOG grading. Patients receiving radiation alone or with chemotherapy were included, while those without cancer or receiving only chemotherapy, targeted, or hormonal therapy were excluded. Data were obtained from treatment charts, radiation cards, laboratory reports, and patient interviews. Adverse events were identified, confirmed with oncologists, graded as per RTOG criteria, and analysed for treatment patterns and management outcomes. Results: Among 315 female breast cancer patients, most were aged 51-60 years (51.7%) with invasive ductal carcinoma (62.2%) as the major subtype. ER positivity was seen in 46%, and early-stage disease (Stage 0-I) in 60.3%. Adjuvant therapy predominated (60.9%), with EBRT (78.7%) as the main modality. Common radiation-related adverse events were fatigue (73.9%), dermatitis (42.8%), breast pain/swelling (31.1%), nausea and gastritis (16.2% each), hyperpigmentation (8.6%), and pneumonitis (6.0%). Most were mild to moderate (RTOG 1-2) and managed supportively. However, 18-35% of cases, mainly fatigue and dermatitis, lacked intervention, indicating a need for improved supportive and pharmacist-led care. Conclusion: Radiation therapy is well tolerated in breast cancer patients, but proactive, multidisciplinary care and continuous monitoring are essential to manage adverse events and optimize patient outcomes.