A total of 11,247 purebred animals were registered in Korea in 1980. The distribution of the registered animals by breed was 44.3! for the Landrace, 25.8 for the Large Yorkshire, 17.1 % for the Duroc, 8.2% for the Hampshire, 2.3% for the Berkshire, 2.0% for the Spotted and 0.1% for other breeds. On-farm testings of boars are being conducted at certain private swine breeding farms and National Livestock Breeding Station in Korea. A boar testing program was initiated in the spring of 1981 at the Livestock Experiment Station with the boars consigned by private breeders. However, due to the limitation of the testing facility at the Station, it is highly desirable to establish a new central boar testing station in the near future. The boars tested at the central station can be selected primarily on the basis of growth rate, feed efficiency, backfat thickness and structural soundness. On-farm testings of boars and gilts at private swine breeding farms are encouraged. The use of sow productivity index for selection of sow is also suggested to improve the litter size and milking and mothering ability. The population structure desired is the pyramidal shape with the nucleus herds on the top, multiplier herds in the middle to produce hybrid gilts, and the commercial herds for pork production at the bottom. The testing and selection programs should be concentrated on the nucleus herds, and the desirable genetic materials in the nucleus herds should be passed on to the commercial herds through the multiplier herds. For full utilization of heterosis in commercial swine production, a 3-breed terminal cross is suggested for large scale swine operation, for example, using the Landrace and Large Yorkshire as dam breeds to produce hybrid gifts and the Duroc, Hampshire, or tile Spotted as a terminal sire breed. A rotation crass or a static rotation cross may also be useful under certain circumstances.