It has been well known that the family pjanning programme has a great deal with declining fertility in Korea. The present study was aimed to measure the impact of family planning program me on fertility level. The specific objectives are to overview the demographic changes ncluding fertility declining and to calculate actual number of birth averted during the last 20 years. The data used for the present study was collected from various sources such as service statistics of the government, survey and research reports, and other related papers. The tool used for calculation of birth prevention was "Standard Couple Years of Protection (SCYP) Method" developed by M Gorosh. The major findings are summarized as follows ; Total of family planning acceptors from 1962 to 1982 was 9,556,153. On the basis of this data, total of averted births was calculated for eachcontraceptive Method ; 1.Oral pills, total number of acceptors from 1968 to 1982 was 2.347,259. Estimated number of birth averted was 272 ,303 .70 and the Coefficient of births prevention per acceptor turned out to be 0.114 2.Condoms, total number of birth acceptors from 1962 to 1982 was 2,874,216. Estimated number of birth averted was 220,495.30 and the coefficient of births prevention per acceptor turned out to be 0.077. 3.IUD, total number of acceptors from 1962 to 1982 was 5,101 .650. Estimated number of birth averted was 1,377,584.76 and the coefficient of births prevention per acceptor turned out to be 0.270. 4.Vasectomy, total number of acceptors from 1962 to 1982 was 556,508. Estimated number of birth averted was 626 ,128 .80 and the coefficient of births prevention per acceptor turned out to be 1.125. 5.Tubaligation total number of birth acceptors from 1972 to 1982 was 1 210,775. Estimated number of birth averted was 1 ,117 679.00 and thecoefficient of birtlts prevention per acceptor turned nut to be 0.923. 6.Abortion, total number of acceptors from 1973 to 1982 was 465,525. Estimated number of birth averted was 355 ,283 .60 and the coefficient of births prevention per acceptor turned out to be 0.763.