386 sera were examined with three commercially available ELISAs for antibodies to HTLV-III. Western Blot and an indirect immunofluorescence assay were performed on sera showing a positive reaction in one or more ELISAs as confirmatory assay. 299 sera reacted negatively in all ELISAs, 48 were positive in all ELISAs and the confirmatory assays, whilst 33 ELISA positive sera reacted negatively in the confirmatory assays. In the case of 5 sera both Western Blot as well as the immunofluorescence assay had to be undertaken to obtain conclusive results.