A possible application of feed lot feeding, (free choice v.s. non free choice) and their effects on reproductivity of Korean cow was studied. A total of 24 pregnant cow were divided into 3 groups in equal number as following. A Group: Feed lot feeding and free choice. B Group: Feed lot feeding plus pasturing and non free choice. C Group: Stall-feeding and non free choice. The experiment w-as conducted between 1st May and 20th December, 1973. Throughout the studies the following experimental results were obtained and summarized. 1. Twenty-four of A, B and C groups of test cows showed normal parturition. And it was shown that the reproduction of A group was not adversely affected if they were fed adequately. 2. No group difference in birth weight of calves and the return estrus of cows were observed. Average birth-weight of A, B and C groups was 24.4㎏, 22.9㎏ and 23.5㎏ respectively. The return of estrus of A, B and C group cows showed 52.3 days, 50.1 day`s and 54.0 days respectively. 3. No group differences in estrus cycle and estrus duration v-ere observed. The estrus cycle of A, B and C group cows was 20.5 days, 21.8 days and 19.8 days respectively. The duration of estrus of A, B and C group cows showed 41.7 hours, 44.8 hours and 39.0 hours, respectively. 4. Body weight gain of calves at 210 days of age of A, B and C group calves were 148.0㎏, 140.1㎏ and 121.4㎏ respectively, and A group was the highest while C group was the lowest. 5. Daily milk consumption of calves during the first and second months after parturition were 4.04㎏ for A group and 3.82㎏ for B group. 6. Climatic condition duirng the experiment was as follows. A maximum temperature ranging 31℃ to 36℃ were recorded for 33 days, while a minimum temperature ranging -4℃ to -11℃ was recorded for 18 days respectively. Rainfall was recorded for 59 days and a maximum fall in a day was 44.3㎜.