Worldwide, Chlamydia trachomatis is the most common bacterial sexually transmitted disease. Advances in our understanding of this infection in recent years have come from the cloning of its genome, improved understanding of its pathophysiology, and through amplified DNA testing. Coupled with effective therapies, prevention through screening has become a priority. This review updates the reader on developments in chlamydial infection in women in the areas of pathophysiology, diagnosis, prevention, and treatment. Hopes for a vaccine are briefly discussed.