A comparative study was done between the immunogenic response induced in two groups of one week old chicks vaccinated with formalin-inactivated and binary ethyleneimine (BB) vaccines of avian Reo virus. Chickens were bled weekly for 8 weeks post-vaccination and tested for neutralizing antibodies. Vaccinated and non-vaccinated control groups of chicks were challenged with virulent virus at the 3"¹ week post-vaccination. Chicks immunized with binary ethyleneimine inactivated vaccine had a higher level of serum neutralizing antibodies. However, both vaccinated groups were protected when challenged.