Introduction: Covid 19 pandemic has affected the delivery of health care particularly cancer care services throughout the world. Excess health care services were used to manage this pandemic and its complications. So, the shift in health care caused gaps in cancer screening services and treatment which got reflected in the fall of cancer entries in hospital-based cancer registry(HBCR). Methods: Tirunelveli hospital-based cancer registry data were collected from the year 2016 to 2020. The entries made during the year 2016 -2019 were tabulated. For the pandemic year 2020, cancer case incidence at various sites for each month are collected and tabulated and the fall in total cancer cases were analysed Results: There is steady increase in total cancer cases entry in HBCR from 2016 __ampersandsignndash; 2019. There is decreased total cancer case entries during the pandemic year 2020 compared to previous years from 2016-2019. In April __ampersandsignndash; July 2020, during the peak of pandemic there is low cancer case entries in HBCR. This reflects there is shift in health care services delivery towards control and treatment of pandemic cases rather than to cancer care services. Conclusion: The impact of Covid 19 pandemic on cancer cases in the tertiary care hospital in south Tamilnadu has resulted in decrease and delay in identifying new cancer cases and treatment delivery. These problems if unsolved will result in increased cancer burden and mortality for the upcoming years.