Background and Objectives Sparse data exist for quantifying the association between Chlamydia trachomatis infection, salpingitis, and tubal infertility. Goal of This Study To investigate the impact of Neisseria gonorrhoeae and C. trachomatis in tubal infertility. Study Design This was a multicenter case-control study that compared women who have bilateral tubal occlusion with other infertile women and age-matched pregnant control subjects. Reproductive and sexual history were recorded, and inmmunoglobulin G antibodies to C. trachomatis and N. gonorrhoeae were measured. Results Women with past chlamydial or gonococcal infections or both were significantly more likely to have bilateral tubal occlusion. The majority of women with bilateral tubal occlusion reported no history of pelvic inflammatory disease symptoms. Other infertile women had a prevalence of C. trachomatis antibodies (60%), which was similar to that of patients with bilateral tubal occlusion (71%). Conclusion Sexually transmitted infections, especially C. trachomatis, are associated with tubal infertility. Because they usually cause no symptoms, public health efforts to prevent tubal infertility should focus on identifying infections in the lower genital tract before they ascend.