Rotaviruses are the single most important cause of severe diarrhea in young children all over the world. VP7 is the major outer capsid and is a primary candidate for inclusion in a subunit or recombinant vaccine. Part of the VP7 gene containing all the three antigenic regions was expressed as a chimeric protein with glutathione S-transferase (GST) in E. coli. The chimeric protein, representing about 30% of the total protein of the recombinant-plasmid-carrying bacteria, reacted with polyclonal antibodies raised against whole virus. Immunization of sero-negative rabbits and mice with purified fusion-protein generated both virus-binding and neutralizing antibodies.