Technical Abstract: Coccidiosis is a ubiquitous intestinal infection caused by many species of Eimeria protozoan that seriously impairs the growth and feed utilization of livestock and poultry. The ability to vaccinate for the control of coccidiosis would have a major impact on the poultry industry and reduce the current annual loss of over $440 million world-wide. Development of novel strategies toward coccidial vaccine development is urgently needed. In this report, a new approach to identify potential coccidial vaccine antigens is discussed. This approach involves: 1) identification of the sporozoite receptor proteins of Eimeria responsible for recognition and penetration of host lymphocytes, and 2) investigation of the ability of recombinant receptor proteins to elicit protective immunity that block parasite invasion of host cells. Identification of the Eimeria-specific epitopes involved in the invasion of the host cells is crucial for the development of a practical and effective immunological control strategy for this disease.