Total viable cells and lactose non-fermenting cells were counted from animal feedstuffs (n=65). And isolation of Gram negative lactose nonfermenting enterobacteria and antibiotics susceptibility of isolates were performed. 1. The ranges of total viable cells / lactose non fermenting in animal feedstuffs from Korean cattle were counted as 9×10-1×10/1×102-6×10, milking cow as 1×104-2×108/2×102-8×10, pig as 1×104-1×106/2×102-6×104, and chicken as 7×l04-1×109/4×102-1×105 cfu/g, respectively. 2. Among the 214 isolates from feedstuffs, 87 from Chinan(n=23), 66 from Changsu (n=23) and 61 from Mooju(n=19) were isolated. Of these isolates, 60 from pigs (n=19), 51 from milking cows(n=15), 45 from chikens(n=11) and 58 from Korean cattle(20) were isolated. 3. Among the 6 genuses of Gram negative lactose nonfermenting enterobacili, Sal-monella sp, Y pseudotuberculosis, Ent agglomerans and Sal choleraesuis were frequently encountered. 4. A majority of isolates were sensitive to 19 antibiotics, singly or in combination. These isoates were completely susceptible to Cp, Gm, Imp and Pi, 93% to Ak and To, 73% to Cax and Ts, 66% to Cit and Tim, 46-53% to Caz, Cf and Cz, 33-40% to Am, Azt, Cfz and Ti, and 6% to Cfx, in order, but not susceptible to Crm. 5. Among the antibiotic resistant strains, a total of 23 resistant patterns was noted, and of these Crm 40(18.7%), Am Cf Cfx Cfz Crm Ti 27(12.6%), each of Azt Ctx Crm and Azt Cax Caz Cft Cfx Crm 22(10.3%) were frequently encountered.