Chronic inflammation induced by Chlamydia trachomatis can lead to tubal factor infertility (TFI). To investigate the genetic basis of chlamydial TFI and various manifestations of tubal damage, we studied functional polymorphisms in selected cytokine genes (IL-10 -1082 A/G, -819 T/C, and -592 A/C; IFN-gamma +874 T/A; TNF-alpha -308 G/A; TGF-beta1 codons 10 T/C and 25 G/C; and IL-6 -174 G/C) in 114 women with laparoscopically verified TFI (hereafter known as "cases") and in 176 controls. Evidence of past infection with C. trachomatis was demonstrated in 96 cases by use of a combined test for humoral and cell-mediated immune responses to chlamydial elementary bodies (EBs) and chlamydial heat-shock protein 60 antigens. We found that the IL-10 -1082 AA genotype and the TNF-alpha -308 A allele increased the risk of severe tubal damage in women with infertility associated with C. trachomatis (odds ratio [OR], 7.3 [95% confidence interval {CI}, 1.3-42] and 4.0 [95% CI, 1.0-16], respectively), suggesting that differences in these genes contribute to the wide spectrum of disease manifestations.