This study was conducted not only to evaluate the feed value for forests and organically produced-agricultural byproducts, but also to determine effects of different hilly pasture types on feed intake, nutrient digestibility and nitrogen retention in Korean black goats. Forty black goats were employed in the feeding trial and they were separated into four treatments (forages grown in chemical fertilizer, organic forages, native plants and browses) with 10 goats for each treatment. Furthermore, 12 goats, for nutrient digestibility trial, were allotted to few treatments of three goats per treatment with a randomized complete block design. Total body weight gain and average daily gain were significantly (p<0.05) decreased in the order of forages grown in chemical fertilizer, organic forages, native plants and browses throughout the trial. Dry matter intake (DM), digestible DMI, DM digestibility and nitrogen retention were highest in forages treatment grown in chemical fertilizer (p<0.05). From the above results, Organic Korean black goats fed forest byproducts as forage source and domestic organically produced-agricultural byproducts as supplemental diets were somewhat lowered in their performance. However, it showed high stability in the sustainable farming of organic Korean black goats. As the result, the consumption of organic Korean black goats might be more desirable for medicinal use rather than fur meat as a table food. The way to increase the low performance of organic Korean black goats for supplemental diets might be the additional supply of lacking nutrients for supplemental diets