A total extract of Setaria equina adult worms was used as antigen in the enzyme-linked immunosorbant assay - ELISA - for serological diagnosis of Wuchereriasis. Patients were included with a parasitological diagnosis of Wuchereriasis, with other diseases, as well as clinically normal individuals, in a total of 139 cases. The high titers observed for Wuchereriasis patients indicated a close antigenic community between S. equina and W. bancrofti. However, the frequent reactivity found in other parasitic diseases, especially intestinal parasitoses, suggests antigenic fractions should be investigated which could furnish higher specificity in the test.