The purpose of this study was to evaluate women's knowledge about cervical cancer, Pap smears, and human papilloma virus in relation to their cervical cancer screening behavior. This hospital-based study was conducted with a sample of 200 women: 100 women screened in the last three years and 100 non-screened women who attended a hospital located in the metropolitan area of Buenos Aires, between September 2008 and February 2009. Women at the hospital were surveyed using a structured questionnaire. Multiple logistic regression models were used to evaluate the relation of women's knowledge about Pap smears to screening behavior, controlling for socio-demographic characteristics. Of the women who had been screened, 49% compared to 73% of those not screened had inadequate knowledge about Pap smears (P = 0.001), and 47% of screened and 30% of non-screened women reported that they had ever heard about human papilloma virus (P = 0.013). In multivariate analysis, having adequate knowledge about Pap smears (odds ratio: 2.6 or 95%, confidence interval: 1.4–4.8) having health insurance (odds ratio: 2.6 or 95%, confidence interval: 1.1–6.4) and being married (odds ratio: 1.8 or 95%, confidence interval: 1.1–3.4) were the factors related to being screened in the previous three years. Knowledge was related to screening. Comprehensive educational approaches may enhance screening for cervical cancer prevention.