Objective : To estimate the significance of the Pap smear as a screening tool for cervical cancer. Methods : A total of 79,840 Pap smear results peformed at Pusan Paik Hospital over the 20 year period from 1979 to 1998 were collected and analyzed. Results : The number of Pap smear cases increased markedly during this period, and the results as a whole were classified as of 96.4% normal and benign cytology, 2.2% pre-cancerous cytology, and 1.4% cervical cancer. The relative frequency of cervical cancer decreased from 1.6% in 1979 to 0.7% in 1998. About 64% of the Pap smears were distributed within the age range of 30 to 49 years, and the rate of cervical cancer increased with age, age of marriage and experience of childbirth (p<0.01). The overall agreement of Pap smear results with histologic diagnosis by one histologic degree was 92.7%(1,128/1,217) with 73 overestimated cases and 16 underestimated cases of Pap smear compared to histologic diagnosis. Conclusion : This result implies that the Pap smear is an excellent screening tool for cervical cancer with respect to both its scale and validity. Periodic and active Pap smear testing would be helpful for the secondary prevention of cervical cancer.