The purpose of the study was to compare different phenotypic methods;M3DT,AmpC disc test with and without EDTA, boronic acid inhibitor test for AmpC detection and screen for ESBL and AmpC production among gram negative isolates from a tertiary health care teaching hospital. Out of 149 cefoxitin resistant isolates, boronic acid method detected 53.02% of AmpC producers. While ESBL was detected in 46.97% of isolates, coproduction of ESBL and AmpC was seen in 30%. Boronic acid inhibitor method was found to be the most sensitive , simple and easy method to perform on a routine basis in the laboratory.