The most widely used cell lines for in vitro studies of Chlamydia trachomatis infections are McCoy and HeLa cells. Our understanding of the intracellular events that occur during ocular C. trachomatis infections may well be improved if such infections could be studied in a host cell that more closely approximates the natural host conjunctival cell. We report here that Chang conjunctival cells, which have been derived from human conjunctival cells, can be infected with C. trachomatis, serovar B. The optimal times for exposure of the host cells to infectious material and to cycloheximide are about 24 and 48 h, respectively. Under these conditions, the maximum number of inclusions is observed at 72 h after centrifugation.