CONTEXT:Most US women who have undergone hysterectomy are not at risk of cervical cancer-they underwent the procedure for benign disease and they no longer have a cervix. In 1996, the US Preventive Services Task Force recommended that routine Papanicolaou (Pap) smear screening is unnecessary for these women. OBJECTIVE:To determine whether Pap smear screening among women who have undergone hysterectomy has decreased following the recommendation. DESIGN:We used data from the Behavioral Risk Factor Surveillance System (1992-2002), an annual, population-based telephone survey of US adults conducted by the Centers for Disease Control and Prevention. Data about timing, type, and indication for hysterectomies were obtained from the Nationwide Inpatient Sample and other sources. STUDY PARTICIPANTS:In each year of the survey, a representative sample of US women 18 years and older who had undergone hysterectomy (combined n = 188,390) was studied. MAIN OUTCOME MEASURE:The main outcome was the proportion of women with a history of hysterectomy who reported a current Pap smear (within 3 years). Overall proportions are age adjusted to the 2002 US female population. RESULTS:Twenty-two million US women 18 years and older have undergone hysterectomy, representing 21% of the population. The proportion of these women who reported a current Pap smear did not change during the 10-year study period. In 1992 (before the US Preventive Services Task Force recommendations), 68.5% of women who had undergone hysterectomy reported having had a Pap smear in the past 3 years; in 2002 (6 years after the recommendation), 69.1% had had a Pap smear during the same period (P value for the comparison =.22). After accounting for Pap smears that may have preceded a recent hysterectomy and hysterectomies that spared the cervix or were performed for cervical neoplasia, we estimate that almost 10 million women, or half of all women who have undergone hysterectomy, are being screened unnecessarily. CONCLUSIONS:Many US women are undergoing Pap smear screening even though they are not at risk of cervical cancer. The US Preventive Services Task Force recommendations either have not been heard or have been ignored.