In the 1920s, when George Papanicolaou began to develop the screening test that now bears his name, the cause of cervical cancer was not known, and the cancer was a common cause of death among women. Since Papanicolaou testing entered clinical practice in the 1950s, however, cervical cancer incidence and mortality have markedly decreased in the United States. In 2014, there will be an estimated 12 360 new cases of cervical cancer and 4020 deaths attributable to the disease.1