A serological survey of Piry was undertaken of the sera of inhabitants of Catolância-Bahia State, Brazil. Serum results obtained by a vesiculovirus neutralization test of C6/36 cells read by ELISA are compared with those obtained by the classic technique, carried out on newborn mice. The agreement between the results was as high as 98.7% of the 204 sera tested and the neutralization test of C6/36 cells was chosen as the most suitable technique for the sero-survey testing.