Resistance by virtue of production of ESBL in gram negative bacteria is an emerging problem leading to therapeutic failure when β-lactam drugs are used. However, their presence may be missed while using routine disc diffusion methods for antibiotic susceptibility testing. All isolates of E. coli, K. pneumoniae, K. oxytoca and P. mirabilis were studied for ESBL production by CLSI recommended Phenotypic confirmatory test (PCT ) and Double disk approximation test (DDAT). Out of 10,055 clinical samples,1738 study isolates were obtained of which 1196 were E. coli (68.82%), 465 K. pneumoniae (26.75%), 17  K. oxytoca (0.97%) and 60 P. mirabilis (3.46%). 43.10% (749 out of 1738) study isolates were confirmed to be ESBL producers. The best sensitivity was found for Tigecycline (100%) followed by Polymyxin B (91%) and Imipenem (81%). To conclude, we found a very high prevalence of ESBL producers (43.10 %) in our hospital especially from the IPD wards.