A study was conducted to assess the impact of Mega Sheep Seed Project (MSSP) funded by the Indian Council of Agricultural Research (ICAR) for Mecheri sheep to quantify the improvement in reproductive traits and survivability. The study involved three types of flocks viz., nucleus flock at farm, beneficiary flocks and non- beneficiary flocks in Salem and Karur districts (Tamil Nadu). The age and weight at first service, age at first lambing and lambing interval significantly (P<0.05) decreased and lambing rate significantly (P<0.05) increased in MSSP beneficiary flocks compared to non-beneficiary flocks. There was no significant difference in weight at first service, at first lambing and at second lambing before and after implementation of MSSP. Pre-weaning, post-weaning, adult and overall mortality of Mecheri sheep at MSSP beneficiary flocks was significantly (P<0.05) lower compared to the non- beneficiary flocks. It was found that MSSP had a positive impact on the reproductive and health performance of Mecheri sheep flocks.