This paper introduces the Korea Citation Index (KCI) and also some macro statistics of KCI. KCI started service since 2008 by the National Research Foundation of Korea (NRF), but the data has been gathered from 1998. Our findings are as follows: heavy reliance on books in humanities, but papers as the main reference in all other disciplines. Impact factor is an increasing trend in all disciplines. Social science has the highest impact factor among all fields. In some fields even in science and engineering areas, there are more KCI papers than Korean JCR papers and impact factors of the KCI are higher than JCR. As for the distinction between nationally and internationally fields or journals, some disciplines in social science are clearly nationally oriented. NSE journals listed in both KCI and JCR, however, are not clear in terms of impact factor, but clear in terms of the numbers of papers.