Polymorphisms in cytokine genes can influence immune responses to human papillomavirus infection, possibly modifying risks of cervical cancer. Using an amplification refractory mutation system-polymerase chain reaction method, we analyzed a single nucleotide polymorphism (A/G) at position -1082 in interleukin-10 promoter region in 440 Japanese women: 173 women with normal cytology, 163 women with cervical intraepithelial neoplasia and 104 women with invasive cervical cancer. The carrier frequency of interleukin-10 -1082 G alleles associated with higher interleukin-10 production increased with disease severity: 9.8% for normal cytology; 19.6% for cervical intraepithelial neoplasia; 29.8% for invasive cervical cancer (P for trend < 0.001). Among cytologically normal women, human papillomavirus infections were more common in those who were positive for an interleukin-10 -1082 G allele (P = 0.04). In conclusion, our data suggest that interleukin-10 -1082 gene polymorphism may serve as a marker of genetic susceptibility to cervical cancer among Japanese women.