Gram negative bacilli (GNB) continue to be an important cause of health care associated infections. Antimicrobial resistance among these bacilli is increasing on a worldwide basis, especially resistance against β lactam antibiotics due to the development of β lactamase enzymes. Carbapenam which were considered drug of choice are now showing resistance. Thus, β lactamase inhibitors should be investigated as a therapeutic option by combining them with the respective cephalosporins/monobactam. Newer combinations like Cefepime tazobactum can be a possible carbapenem saving strategy for de-escalation as well as upfront usage in hemodynamically stable patients in ICU. The study was conducted for the period of six months from November 2010 to April 2011 in a tertiary care cardiac centre at New Delhi, India. Sensitivity pattern of 1009 gram negative isolates was tested against cefepime tazobactum, cefoperazone sulbactam, piperacillin tazobaztam, meropenem, imipenem. The incidence of ESBL in our studies was found to be 74. 6%. The sensitivity of E.Coli, Klebsiella pneumoniae, Proteus mirabilis to Cefepime tazobactum was 86.03%, 41.5% 95.2% respectively. The results showed significant differences in the sensitivities for these antibiotics. Increasing antimicrobial resistance among gram negative organisms is a growing concern. Among all β lactam inhibitor combinations tested, Cefepime Tazobactam revealed the highest activity against ESBL producing E.coli and Klebsiella pneumoniae. Further studies are needed to evaluate these combinations in clinical settings as they can play important role for the clinicians as viable alternative to carbapenems.