Samples of single sera collected from 38 patients with different clinical diagnosis were studied in order to perform ELISA techniques with the purpose of detecting poliomyelitis IgG and IgM antibodies. The résults were compared through antibody titration by neutralization test. 21 pairs of sera from infants suffering from acute flaccid paralysis were studied by ELISA-IgM, ELISA-IgG and neutralization test. Stool samples were collected from 20 of the latter patient. Wild poliovirus type 1 was isolated in 8 cases. ELISA-IgM technique was positive in 14 cases. The true positive poliomyelitis diagnosis was based on the persistence of flaccid paralysis 60 days after the onset and on wild poliovirus isolation with significant increase in antibody level. 16 cases were classified as poliomyelitis, 2 cases as non poliomyelitic paralysis and 3 cases as undetermined. 16 out of the 18 well established diagnosis were in agreement (88.8%) with the detection or not of IgM antibodies by ELISA. The specificity of these IgM ELISA antibodies was examined by studying 11 cases of lymphocytic meningitis. Cross reaction in serological responses between polioviruses and coxsackieviruses was observed. These cross reactions should be evaluated by studying a greater number of cases. The poliovirus ELISA-IgM is a sensitive, economical and rapid method to be used in poliomyelitis diagnosis to complete the neutralizing test and virus isolation.