Microbiological investigations and clinical follow-up were performed on 516 patients undergoing first-trimester termination of pregnancy, over a 2-year period. Chlamydia trachomatis was isolated by pre-operative microbiological screening in 6.7% of patients, gonococcus in 0.4% and Trichomonas vaginalis in 2%. Candida spp and Gardnerella vaginalis were isolated from 16% and 28% of the women, respectively. Patients who had positive cervical chlamydial isolation were significantly younger (less than 22 years) than those who did not. Doctor's clinical diagnosis of genital tract infection was found to be associated with a positive screening result but not with the likelihood of postabortal pelvic infection. Among the 175 patients followed up in the outpatient clinic, 4 of the 15 patients with a positive result for N. gonorrhoeae, C. trachomatis and/or T. vaginalis developed postoperative pelvic infection, which is significantly more than the group who did not harbour any of these three organisms (9/114).