The main purpose of this study was laid on vital statistics concerning basic factors of births, deaths, marriages, and divorces including changes in population growth of the Korean population in Japan. An analysis, one of series of demographic-ecological studies on Vital Statistics from 1965 to 1975 issued by the Ministry of Health and Welfare of Japan was undertaken in order to study the recent trends of the Korean population in Japan and compare it with the Japanese population. The major findings are summarized as follows. 1) The Korean population in Japan has been slightly increasing yearly, and the average annual growth rate was 1.05 percent per year from 1965 to 1975.The ratio of total dependent population has decreased from 57.1 percent in 1965 to 50.8 percent in 1975, but it is expected to show a little increase in the near future. 2) Trends in crude birth rate and crude death rate from 1965 to 1975 have steadily declined, while natural increase rate was higher than that of Japanese.The crude birth rate and crude death rate of the Korean population in Japan in 1965 were 21.7 and 5.7 per 1, 000 population, in 1975, 17.9 and 4.7 per 1, 000 population, respectively, whereas the corrected death rate was rather higher than the Japanese. More interestingly, it is concluded that the Japanese folk superstition of Hinoe-Uma in 1966 seemed to be a factor influencing the crude birth rate, stillbirth rate of Koreans in Japan, whereas the extraordinary passing phenomenon was not showed in Korea. 3) The infant death rate has declined very rapidly from 15.8 in 1965 to 8.2 per 1, 000 live births in 1975 and stillbirth rate was also declined from 56.3 in 1965 to 40.5 per 1, 000 total births in 1975. 4) Major cause of death have remarkably changed due to the efficient public health services. Malignant neoplasms, cerebrovascular disease, heart disease were for the three leading causes of death of the Korean population in Japan in 1975. Specific death rates by major causes of death of Koreans in Japan for liver cirrhosis, accidents, suicide, and pan-tuberculosis were higher 38.0, 38.5, 22.4, and 12.8 per 100, 000 population in 1975 than that of the Japanese, respectively. 5) Marriages of Koreans in Japan have increased and the crude marriage rate was 9.8 in .1965 and 11.2 per 1, 000 population in 1975, slightly higher than that of Japanese . It is more considered that the intermarriages of the Korean-Japanese bridegroom or bride have increased and it will overwhelm the level of Korean-Korean marriages in a few years, and general divorce rates have tended to increase following the Japanese.