Clinical assessment of women with pelvic pain was a poor indicator of disease seen at laparoscopy. Thus, of 109 women, 22 at laparoscopy had salpingitis, 19 had adhesions without salpingitis, 20 had endometriosis or ovarian pathology and 48 no observable abnormality. In all laparoscopic categories, Ureaplasma spp. and Mycoplasma hominis, but not Mycoplasma genitalium, were at least as common in the cervix/vagina as Chlamydia trachomatis and equally frequent in the endometrium. However, C. trachomatis had the greatest propensity for spread to the Fallopian tubes. Thus, of 28 women who had C. trachomatis organisms in the vagina/cervix, 13 had them in a Fallopian tube (ratio 2.2:1); the ratio was 6:1 for Neisseria gonorrhoeae, 8:1 for M. genitalium, 21:1 for M. hominis and 31:1 for Ureaplasma spp. M. hominis organisms in a large number were detected most often in women with salpingitis. The likelihood of spread of Ureaplasma urealyticum and U. parvum from the lower to the upper genital tract was about the same and they were detected only once each in a tube, which was not inflamed in either case. Multiple bacteria were often detected at a single site, making it difficult to establish the exact cause of disease. However N. gonorrhoeae was considered to be the sole cause of salpingitis in one woman and the primary or equal primary contributor in four others; C. trachomatis was involved in at least 11 women, mostly as the sole cause or as the primary contributor; M. genitalium was considered the cause in one woman and had possible involvement in three others; and M. hominis was a questionable sole cause in one woman and the primary or equal primary contributor in three. Serologically, C. trachomatis was related to adhesions, without salpingitis, more often (63%) than any other micro-organism. M. genitalium may have been implicated in one case. Serologically, a previous C. trachomatis infection was indicated in 40% of women without an observable laparoscopic abnormality. C. trachomatis in the endometrium and tubes of women without any laparoscopic abnormality suggests subclinical disease, endometritis or endosalpingitis. There was evidence for a smaller proportion (19%) of women without an abnormality having been infected previously with M. genitalium. To some extent this is consistent with the infrequency of acute M. genitalium infections in this cohort of women.