This study was aimed to evaluate mixed sowing rye with legumes under different cattle manure levels for optimum forage yield and organic Hanwoo cattle carrying capacity from 2012-13 to 2014-15. Experiment was conducted under split plot arrangement having 3 main plots (Sole Rye, Rye with hairy vetch and rye with pea) and 4 sub-plots (0, 50, 100 and 150 kg N/ha). Findings showed if rye was mixed cropped with hairy vetch, dry matter (DM) and total digestible nutrient (TDN) yield was not different (P>0.05) from control, whereas rye-vetch mixture had increased (P<0.05) crude protein (CP) yield and carrying capacity for Hanwoo heifers than that of rye monoculture. DM and TDN yield under 100 kg manure was higher (P<0.05) than control and 50 kg N/ha levels but not different (P>0.05) with that of 150 kg N/ha. Manure levels did not affect (P>0.05) protein yield. The carrying capacity for Hanwoo heifers was not different among zero, 50 and 100 kg manure levels, whereas it was higher at 150 kg N/ha (P<0.05) than all other manure levels. Similarly, results depicted little different pattern when rye was mixed sown with pea that DM and TDN yield was not different (P>0.05) when compared with rye monoculture, whereas CP yield was higher in mixed forage than control but carrying capacity was higher (P<0.05) at all manure levels except 150 kg N/ha. It was concluded from findings of present study that mixed growing strategy of rye with local hairy vetch didn’t need any manure application for optimum crude protein yield, whereas 100 kg N/ha manure would be adequate for overall optimum forage yield and 150 kg N/ha needed for obtaining optimum carrying capacity for Hanwoo heifers. Similarly, Rye pea mixed culture didn’t need manure application for optimum crude protein yield but 50 kg N/ha manure would be needful for adequate dry matter yield and carrying capacity for Hanwoo heifers. However, 100 kg N/ha manure could be sufficient for optimal yield of digestible nutrients.