To overcome the growing burden of COVID-19, Tamil Nadu, a southern state in India with a population of 76 million, introduced a strategy for COVID-19 vaccination by campaign mode on a large scale named as “mega-camps”. 38 mega-camps were conducted every weekend for a period of one-year from 2021-22 with 1,108,557 vaccination sessions. Of the total first, second and precaution doses provided, 29%, 53%, 75% were achieved through mega-camps. Also, it helped in reducing vaccine wastages drastically from 6% to -0.30%. In situations, where large vaccination coverage is desired over short period, campaign mode may be preferred in achieving maximum coverage.