We evaluated 104 women hospitalized with a diagnosis of acute salpingitis to compare the relationship between the menstrual cycle and onset of acute chlamydial and/or gonococcal salpingitis and acute salpingitis associated with other facultative aerobic and anaerobic bacteria. Neisseria gonorrhoeae was recovered from 42 women (40%), Chlamydia trachomatis from 28 (27%), and nongonococcal, nonchlamydial organisms only from the upper genital tract in 48 (46%). Among 37 cases with symptoms of acute salpingitis within seven days of onset of menses, 30 (81%) had chlamydial and/or gonococcal infection. Of 35 cases with onset after 14 days postmenses, 23 (66%) had nongonococcal, nonchlamydial organisms only. Of the 28 women with chlamydial infection, 17 (57%) had the onset of disease within one week from the first day of their last menstrual period. Similarly, 23 (55%) of gonococcal infections had onset of symptoms within one week from onset of menses. However, only seven (14%) of the women with nongonococcal, nonchlamydial salpingitis reported onset of symptoms within one week. The temporal pattern of onset of chlamydial or gonococcal acute salpingitis showed significant differences when compared with the time of onset for nongonococcal, nonchlamydial acute salpingitis.