This experiment was carried out to determine the effects of seeding rates and nitrogen fertilization levels on the yield. carbohydrate reserves in stubble and stand reduction of sorghum-sudangrass hybrid (Sorghum bie%r (L.) Moench) in 1983 on the Experimental Livestock Farm, College of Agriculture, Seoul National University in Suwon. The results of this experiment are summarized as follows: I. There was no significant difference in forage yield among three seeding rates(20, 40. and 80kgjha), but there was a significant difference(P <.0 I) in forage yield among three N fertilization levels(O, I 50. and 300kgjha). High nitrogen plot showed the highest dry matter yield. 2. Carbohydrate reserves were influenced not only by seeding rates, but also by nitrogen fertilization levels at first cut(P < .05). At second harvest, no treatments affect the carbohydrate reserves. 3. Only the seeding rates affect the stand reduction at first harvest. But the mortality was influenced by seeding rates and N fertilization levels(P < .05). The high seeding rates caused the high mortality. 4. According to the results obtained from this study, it is suggested that the seeding rate of 40 kgjha and nitrogen fertilization of 300kgjha would be recommendable for maximum forage yield and good performance where sorghum-sudangrass hybrids are broadcasted for summer forage production.