Commercially produced fluorescein labelled monoclonal antibodies for Chlamydia trachomatis detection have been recently become available. We have compared the data obtained using two monoclonal antibodies, one for detecting inclusion on cell cultures (culture confirmation) and the other for detecting C. trachomatis in smears from urethral and cervical swabs, with our routine isolation method which utilizes Giemsa staining of cycloheximide treated McCoy cell cultures. We also evaluated an enzyme immunoassay for detecting C. trachomatis antigens in urethral and cervical specimens. The culture confirmation system was slightly more sensitive and simpler than Giemsa staining. Between the results of immunofluorescence direct test and culture there was 96.3% agreement. Sensitivity, specificity and predictive positive and negative value were 72.2, 98.4, 80 and 97.6%. Between results of culture and enzyme immunoassay there was 97.2% agreement. The immunoassay sensitivity, specificity predictive positive and negative value were, in women, 100, 97.1, 63.6 and 100%; in men, 100, 95.7, 81.8, 100%.