In this study, a total of 75 gram negative rods, comprising 44 Pseudomonas spp., 9 Klebsiella spp., 8 Escherichia coli, 6 Enterobacter spp., 4 Acinetobacter spp., 3 Gram negative nonfermentative bacilli and one Proteus mirabilis, which were isolated at the Training Hospital for Chest Diseases in Izmir during September-October were studied. Amoxicillin-clavulanic acid resistance for the bacteria out of Pseudomonas and Acinetobacter strains were found as approximately 30 % and for oxyimino beta-lactams as 41-52 %. Ratios for extended spectrum beta-lactamase production which was determined in Pseudomonas, Klebsiella and Enterobacter strains were 12 / 44 (27.2 %), 1 / 9 (11.1 %) and 3 / 6 (50 %), respectively. Inducible beta-lactamase production in Pseudomonas and Enterobacter strains by direct induction test was determined as the ratios ; 15 / 44 (34 %), 1 / 6 (16.6 %) respectively. Resistance for carbapenems by disk diffusion was found in 18 (24 %) strains for imipenem and in 16 (21.3 %) strains for meropenem respectively. One Acinetobacter and one Pseudomonas which were found as intermediately resistant against imipenem were determined as susceptible to meropenem. In general, according to the MIC values, imipenem resistance in gram negative nonfermentative rods was significantly higher than meropenem resistance (p< 0.05). Moreover, ratio of resistant strains for meropenem by disk diffusion was significantly higher than the ratio according to the MIC values (p < 0.05).