An enzyme immunoassay (EIA) antigen detection system (MicroTrak, Syva), nucleic acid hybridization (PACE 2, Gen-Probe) and polymerase chain reaction (PCR) assay (Amplicor, Hoffmann-La Roche) were evaluated for the detection of Chlamydia trachomatis in a high-risk female population. Of 234 specimens, 42 (18 %) were positive. The respective sensitivity of the EIA, RNA hybridization and the PCR was 81, 90 and 88 %. When additionally performed on diluted specimens, PCR gave positive results for three of four PCR-negative specimens from EIA- and RNA-hybridization-positive women and a sensitivity of 95 %. Thus, both techniques employing gene technology offered a clear improvement in sensitivity over the EIA. Future improvements in the PCR should be directed towards the elimination of polymerase inhibition.