It is considered that the world cattles are classified into three groups; European breeds belonging to B. taurus, Indian breeds belonging to B. zebu indicus and the cross breeds between them.<br>As to the distribution in Asia, Indian breeds prevails in India, Burma, Malaya, Java, Borneo, Celebes, New Guinea; on the other hand, European breeds are distributed from Mongolia, northern part of China to Korea, and the cross breeds in southern part of China and Indochina.<br>The origin of Japanese native cattle is very obscure. However, some speculation has been made according to archiological and historical studies.<br>It is considered that the native Japanese cattle was from Korea, and some Indian cattle might have migrated into Japan about the time when Budhism was introduced into Japan (A. D. 552). The present Japanese cattle is the improved one crossed with European breeds since Meiji era.<br>In the present studies, the blood groups and serum protein polymorphism of East Asian cattle were examined for the first time and gene frequencies among breeds were compared, then the breed relationships were discussed.<br>The blood samples were taken from 127 heads of Yellow cattle (B. indicus) in Formosa, 159 of Korean cattle (B. taurus) in the southern part of Korea, and three major Japanese breeds; i. e. 383 of Japanese Brown cattle in Kumamoto and Kochi Prefectures, 122 of Japanese Black cattle and 156 of Japanese Shorthorn. The data of the only Japanese native cattle, "Mishima" cattle, reported by KIHARA (1965) were referred to in this study.<br>The 36 reagents for blood typing were used to detect the blood antigens belonging to 91oci. Serum transferrin types (JAMIESON, 1965), hemoglobin types (GAHNE, 1961) and serum albumin types (ASHTON, 1964) were determined by the starch gel electrophoresis techiques.<br>The results are summarized as follows:<br>1. The gene frequencies of blood groups and serum protein types in East Asian cattle are distinctly different from those of European cattle which have been reported elsewhere. Also, a considerable amount of frequency differences among the breeds examined was recognized.<br>2. Blood antigenic factor Z', which was found originally in Indian Zebu, is common in all East Asian breeds. The gene Hbc and AlbB, which have not been recognized in European cattle, were found at relatively high frequencies in Formosan Yellow cattle, at low frequencies in Korean cattle, and very rarely in a Japanese breed.<br>3. New variants, Hb-AX, Hb-CY and Tf-DX, as they are named temporarily, are found in Korean cattle, Tf-XX, Tf-EX and Alb-BX in Yellow cattle, and Tf-AX in Japanese Brown cattle<br>4. The differences between expected and observed numbers at four loci, FV, Tf, Alb and Hlb, were not significant, except in Tf locus of Korean cattle, when the value of F=0, and their frequencies were in accordance with Hardy-Weinberg equilibrium.<br>5. Estimates of relative amount of genetic difference among the breeds may be made by summing the absolute gene frequency differences for each of the two-breed comparisons. The results indicate that the Japanese breeds, especially Japanese Brown cattle in Kochi Prefecture, are mored like Korean cattle than Yellow cattle is to the other two. And the differences among Japanese breeds may be due to the degree of the influence of European cattle used for the improvement and to the degree of isolation of the breed.<br>6. Clines of gene frequencies of Tf, Hb and Alb genes among breeds were recognized as shown in Table 10. From these results, it is supposed that Japanese native cattle originated from Karean cattle, which might have been somehow influenced by Yellow cattle. However, the drastic decrease of AlbB and HbB gene frequency from Yellow cattle to Korean cattle suggests that Korean cattle might have originated from other breed than Yellow cattle.