In the middle of the 1980s, the first ESBL isolates were found in Western Europe, and in the late 1980s, they were found in the US. ESBLs are the enzymes that confer resistance against all ß-Lactam drugs (penicillin, 1st, 2nd, 3rd generation cephalosporin’s, monobactams except carbapenems and cephamycin). These enzymes can breakdown the active ingredients in many common antibiotics making them ineffective. ESBL have only been reported in Gram negative bacterial infections. The objective of this study was to determine the frequency of extended-spectrum ß-lactamase (ESBL) producing gram-negative bacilli recovered from clinical specimens in Intensive Care Unit. The Cross-sectional descriptive study was performed from January 2024 to April 2024. The study was carried out at Department of Microbiology Armed Forces Institute of Pathology (AFIP) Rawalpindi. A total of 306 ESBL producing isolates from various clinical specimens sent to AFIP for culture and sensitivity were identified using standard microbiological techniques and tested for antimicrobial susceptibility. At the same time screening for ESBL production was also done. ESBL production was confirmed by combination disc synergy method. A total of 306 specimens that were ESBL producers are included in this study. Urine was the major source of bacterial isolates collected, comprising 76.10% of total samples, Pus 19.60%, Sputum 2%, NBL 1%, Blood 0.70%, CVP Tip 0.70%. E. coli was the most common species isolated from these specimens, comprising 230 (75.2%), Klebsiella Pneumonia was the second 34 (11.1%), Serratia Marcescens 16(5.2%), Proteus Mirabilis 7(2.3%), Serratia ordorifera5(1.6%), Enterobacter Aerogenes 3(1%), Klebsiella oxytoca 3(1%), Enterobacter cloacae 3(1%), Citrobacter freundii 3(1%), Citrobacter koseri 1(.3%).