Am J Obstet Gynecol 1999;180(5):1104–10 To determine the risk of cytologic abnormality on a screening Papanicolaou test for women 50 years old with and without a uterine cervix, a cross-sectional analysis of 21,152 women aged 50 years who had screening Papanicolaou tests between January and August 1995 was performed. A nested 1:1 case-control study of 172 case patients and 172 age-matched randomly selected control patients from the cohort was performed. To control for potential confounders, conditional logistic regression was used to assess the effect of hysterectomy on the risk of an abnormal Papanicolaou test. Compared with age-matched women with a uterine cervix, those who had a hysterectomy had a 10-fold lower risk of a screening Papanicolaou test abnormality ( OR = 0.09, 95%CI = 0.02-0.24). The risk was reduced further among women taking estrogen ( OR = 0.02, 95%CI = 0.004-0.14) compared with women not using estrogen ( OR = 0.14, 95%CI = 0.04-0.56). The reduced risk of Papanicolaou test abnormalities among women aged 50 years who have had a hysterectomy should be considered when individual patients are being counseled, screening guidelines are being formulated, and health care resources are being allocated. Editorial Comment: This study reiterates the concept that cervical transformation zone removal lessens the chance of abnormal cytology. This study notes reduced risk of Pap smear abnormalities in patients greater than 50 years old who have had a hysterectomy. There is a 10-fold reduced risk of having an abnormal Pap smear. The authors state this should be considered when that individual patients are counseled, screening guidelines are formulated, and health care resources are allocated. (LBT)