Turkey flocks recovering from natural and laboratory induced coronaviral enteritis developed lifelong immunity. Virus neutralization tests indicated that neutralization capacity of serums from recovered turkeys was low. One-way cross challenge test using turkeys inoculated with various bluecomb isolates revealed close antigenic relationship or antigenic identity among bluecomb isolates. The controlled application of intestinal preparations containing coronavirus as a vaccination procedure had value in developing active lasting immunity but it has limitations in areas that are attempting to eliminate the disease by a depopulation program. Killed vaccines injected parenterally did not produce a detectable immunity.