The purpose of this study was to determine the antibiotic resistance of Gram-negative bacteria isolated from blood cultures. Resistance to various antibiotics in 96 Gram-negative bacteria isotaled from blood specimens was determined by disk diffusion and BIOMIC system. In addition, extended spectrum beta-lactamase (ESBL) production was investigated in Klebsiella spp. and E. coli strains by double disk synergy method. Resistance to imipenem was not detected while highest resistance was observed against cephalothin. Production rates of ESBL in Klebsiella spp. and E. coli strains were found as 64.7 % and 76.2 %, respectively. These results should be taken into account for initiating empirical therapy of bacteremia when Gram-negative bacteria are suspected.