In order to study the effects of neomycin sulfate on the kidney of Korean black goats after dosing at 36mg/kg(A group) or 18mg/kg of body weight (B group) twice a day, serum chemical values(BUN, SCr), urinary enzyme(GGT) excretion and urinary analysis were checked and renal lesions were observed by light microscope. The proteinuria and granular casts were observed on the 5-6th day and 7th day of treatment with neomycin respectively in the A group. While these changes were observed on the 4th day and the 6th day respectively in one goat of the B group. Urinary GGT excretion began to increase from the 9th day and reached to maximum concentration on the 15th day of treatment with neomycin in the A group. Thereafter, GGT excretion began to decrease and reach to normal level on the 21th day. But GGT excretion increased on the 9th day in only one goat of the B group. Concentrations of BUN and SCr increased on the 12th day in the A group and in one goat of B group. The kidneys were swollen gross pathologically and the renal tubular epithelial cell changes were noticed histologically in the A group and in one goat of the B group. These changes were included degeneration with hyaline droplet formation, flattened epithelial cells and necrotic epithelium. Granular casts were showed in many tubular lumens. Prfesent results indicated that nephrotoxicosis would not occured in Korean black goats dosing with neomycin sulfate less that 36mg/kg of body weight a day.