Six different antigen preparations for use in an enzyme immunoassay (EIA) to detect IgM, IgA and IgG antibodies toBordetella pertussis were evaluated using sera from 13 randomly selected culture-positive patients and from 87 patients with suspected pertussis during a pertussis outbreak. Based on results in 80 healthy control sera a specificity limit of 99.9 % was selected. Sera from all culture-positive patients reacted with at least one of the antigens. The sensitivity of the EIA using the individual antigen preparations was 85 % for filamentous hemagglutinin, 92 % for pertussis toxin, 62 % for 69 kDa outer membrane protein, 85 % for a pool of these three antigens, 54 % for sonicated whole bacteria and 69 % for 21 kDa pertussis toxin subunit S1. In the outbreak patient group 49 (56 %) of the initial sera reacted with at least one of five antigen preparations. The EIA using sonicated bacteria detected only 41 % of all seropositive cases compared with 51 % using filamentous hemagglutinin, 61 % using pertussis toxin, 65 % using 69 kDa OMP and 65 % using pooled antigen. It is concluded that either the pooled antigen or pertussis toxin antigen are suitable antigen preparations for use in the EIA for diagnosis of pertussis.