Chlamydia trachomatis (Ct) infections are difficult to monitor due to their mild clinical presentation and the lack of an ideal diagnostic method. The RENACHLA network covers infections for which microbiological confirmation has been ordered. In the sentinel network, surveillance of male urethritis is solely clinical. Current surveillance systems therefore have a gap in coverage for women seen in private practice. However, two-thirds of Ct infections in women are diagnosed by private gynecologists. GYNECHLA is a network of volunteer gynecologists based in the Paris region that conducted a pilot survey in 1991. The results presented in this article are derived from a series of samples collected between April and June 1993. (adapted from the text).