PURPOSE Delivery of cancer care during the pandemic required adopting various changes in the standard management. We analyzed the impact of the first wave of the COVID-19 pandemic on radiation oncology treatment practices at Tata Memorial Hospital in India. MATERIALS AND METHODS From March 1 to October 31, 2020, all consecutive patients who attended the radiation oncology department for radiotherapy treatment were included in this study. Electronic medical records, patient files, and telephonic consult were used to collect patient's data including changes in the standard treatment practice, COVID-19 testing and its results, and subsequent impact on radiotherapy treatment. Comparison was done with the same period data of 2019 for the number of the caseload, radiotherapy regimen, referral rates, and noncompliance rates. RESULTS Our study included 4,256 patients with a median age of 52 years (interquartile range 41-61 years). There was a significant drop in the new-patient registrations (approximately 63%), radiotherapy consultations (44.9%), and referrals to other centers (27.8%). The reduction in the caseload was highest for genitourinary cases (–58.5%) and the lowest for breast cases (–11.5%) when compared with the 2019 cohort. Among those treated with radical intent, the noncompliance rate was 15%. Hypofractionation was the commonly adopted regimen across all sites. Compared with 2019, the maximum reduction in the average fractions per patient was seen in the breast cancer cases (–8.2 fraction), followed by genitourinary cases (–4.9 fraction). Of the 27.8% of patients tested for COVID-19, 13.4% turned positive and 3.4% died due to the disease. CONCLUSION The COVID-19 pandemic adversely affected the number of radiotherapy consultations and treatments at our institute. However, our department offered uninterrupted services despite grave challenges. Hypofractionated regimen was used across disease sites to minimize patient visits and allow planned treatment completion. Radiotherapy was delivered safely, and patients experienced low rates of COVID positivity during radiotherapy and even lower mortality.