INTRODUCTION: The utilization of Ceftazidime –avibactam (CAZ-AVI) presents as a viable treatment option for infections resulting from multidrug resistant gram-negative bacteria (MDR-GNB). This study aims to evaluate the effectiveness of Ceftazidime-avibactam, a novel antibiotic combination, against MDR GNB isolated from various clinical samples of patients attending a tertiary care hospital of Lucknow during 2023-2024. AIM: The aim of this study was to estimate the effectiveness of Ceftazidime Avibactam on multi drug resistant gram-negative bacilli isolated from various clinical samples MATERIALS AND METHODS: Samples of urine sputum & pus were collected from various patients admitted in ward. The objectives include assessing the antimicrobial susceptibility patterns of MDR isolates using the disk diffusion method and determining the minimum inhibitory concentrations (MIC) of ceftazidime-avibactam using the Epsilometer test (E-test). Additionally, the study compares the MIC results obtained via E-test with those from the broth microdilution method to establish consistency and reliability in susceptibility testing. RESULTS: A total 1472 samples were collected from January to August 2023. Among these, 222 (15.07%) samples were identified GNB. Out of these 100 (45.04%) ESBL isolates were meticulously selected to encompass a spectrum of bacterial species commonly associated with ESBL-mediated resistance mechanismsto isolate MDR GNB, followed by testing for susceptibility to ceftazidime-avibactam. Resistance to ceftazidime- avibactam was observed in 22% of isolates by the BMD method and 23% by E-test, with higher resistance in MBL-producing strains. CONCLUSION: These results highlight the potential of ceftazidime avibactam as an effective therapeutic option for treating MDR infections, underscoring the critical role of robust antimicrobial stewardship and precise susceptibility testing in clinical management.