Korean native cattle has been used for draft animal, however, the worth of the native cattle for farm working decreases rapidly as the mechanization of agricultural production is accelerated in the rural area. The demand of animal products, on the other hand, increases rapidly with the development of national economy. Most of beef consumed in Korea is produced from the; native cattle, therefore, the multiplication and improving beef quality of the native cattle is expected to be effective way in order to meet beef demand in Korea. It is said that Korean native cattle was not suitable for beef production because of their late maturity, small body size and low beef productivity, but the reasons for poor productivity of the native cattle was not yet found out whether from genetic sources or from environmental conditions (especially nutritionally factor). So, these studies were conducted to find out the sources of poor beef production of the native cattle and the results showed that the reasons may be originated mainly from malnutrition and poor mangement to the native cattle. The effects of different levels of nutrition allowed to cows before and after calving on the milk production and growth of calves was investigated. Eighteen Korean native cattles were devided into three groups as 100%, 80%, and 60% of nutritional levels by the Japanese Feeding Standard in order to find out the effects of different nutritional levels fed to cows before and after calving on the milk production of cows and growth of calves. The body weight of cows was weighed for six months from three months before calving to three months after calving, and milk yield of cows and growth of calves were measured for three months after calving. The results showed that body weight gain of cows decreases significantly by the decrease of nutritional level, that is, body weight gain of cows during three months after calving were 33.5㎏ at 100%, 28.3㎏ at 80% and 4.4㎏ at 60% nutritional level. The birth weight of calves was also affected by cows nutritional conditions, as 26.0㎏ at 100%, 25.3㎏ at 80% and 21.4㎏ at 60% of nutritional level of dams, but these difference was not significant. Average daily milk yield of cows were 2.9㎏ at 100%, 3.3㎏ at 80% and 2.9㎏ at 60% of nutritional level, but there were no significant differences.