The total number of persons who underwent uterine cervical cancer screening at the Tokai University Hospital Health Evaluation and Promotion Center during the 25-year period from January 1976 to March 2001 was 30,173 (gross number: 111,181). Since 1995, more than 6,500 females have visited the center annually, and more than 70% were 40-59 years of age. Among these females, 849 exhibited atypical changes higher than class IIIa in the cytological examination (class IIIa: 779, IIIb: 43. IV: 14 and V: 13), and the detection rate was 0.76%. In examining the relationship between the age and number of visits to the center and the detection rate of atypical changes observed in the cytological examination, patients in their 40s exhibited the highest detection rate (1.31%), and the rate at the first screening was 1.19%. Analysis of the age distribution for the detection rate of atypical changes in the cytological examination before 1989 and after 1990 showed that persons in their 40s and 50s had high rates (1.62% and 1.69%, respectively) before 1989, but since 1990 persons in their 20s, 30s and 40s exhibited high rates (2.86%, 2.16% and 2.61%, respectively) (p ＜ 0.001). This suggests a lowering of the age at which atypical changes are observed in the cytological examination.