A case-control study of 418 women with invasive squamous cell cervical cancer and 704 population controls enabled evaluation of risk factors for this relatively rare cancer. Consistent with an infectious etiology was a pronounced effect of multiple sexual partners, with those reporting 10 or more partners being at a significant threefold excess risk. Early first intercourse also was associated with some residual effect on risk, although the relationship was not linear, nor the explanation readily apparent. Those with multiple births were at significantly elevated risks, even after adjustment for sexual parameters. Menstrual and hygiene factors, including use of tampons, vaginal deodorants, and douching products, were not consistently related to risk. Histories of specific infections involving the genital tract were poor predictors of risk, since few women provided positive responses, but those with nonspecific diseases were at a significant twofold excess risk.