The authors analysed the indirect immunofluorescence assay, for the diagnosis of bancroftian filariasis using papain treated W. bancrofti microfilariae as antigen, widely used in Recife-Brazil. Sera from 50 patients with several clinical forms of the disease including asymptomatic carriers, tropical pulmonary eosinophilia, elephantiasis, filarial fever and chyluria were analysed. For the control group, 50 individuals were selected, living at least 5 years in endemic area, with neither previous DEC treatment nor clinical-laboratory evidences of the disease, called normals endemic. The sensitivity and specificity were analysed taking into account different cut off values. It was not possible to differentiate infected individuals from the control group. It was not even possible to establish any correlation with IMF titers among different clinical presentation of the disease. Crossed reactions with various intestinal helminths were considered, but no relationship was found.