Despite the widespread availability and demonstrated efficacy of screening with the Papanicolaou smear, many women are screened irregularly or not at all. This study was designed to identify the barriers that prevent those women at risk for cervical cancer from being screened. Complete cervical cytology screening histories were taken during a population-based case-control study of invasive squamous cell carcinoma of the cervix involving 200 patients and their matched neighborhood controls. Smears taken during the previous 5 years were verified whenever possible. Ordinal logistic regression analysis was used to identify seven factors that significantly (P less than 0.05) and independently predicted regular recent screening among both cases and controls [failure to understand the importance and screening nature of cervical smears (-), expressed fears of embarrassment (-), having had a urogenital infection (+), number of pregnancies during the last 5 years (+), the number of pregnancies for which no prenatal care was sought (-), and knowledge of the recommended screening interval (+)], two variables that predicted screening among cases but not controls [age (-) and number of years of oral contraceptives use (+)], and one that predicted screening only among controls [years of living in the United States (+)]. Education, income, Latin heritage, being married, having a regular physician for one's medical care, and all other methods of birth control were significant predictors of screening in the univariate analyses, but were explained by the other more powerful predictors in the multivariate analysis.