Resistant development in ESBLs producing bacteria to third generation cephalosporin has emerged with alarming rapidity in recent years and become major cause of concern world wide. Therefore, in order to cater growing resistance problem, combination of third generation cephalosporin with beta-lactam inhibitors and Ethylenediaminetetraacetic acid, was studied. The in vitro antibacterial efficacy of various concentration of ceftriaxone +sulbactam and effective dose determination study of EDTA against various ESBLs producing micro organisms such as Escherichia coli (MTCC -739), Klebsiella pneumoniae(MTCC-109),Pseudomonas aeruginosa (MTCC-1688), and Staphylococcus aureus (MTCC-737) were investigated. From the AST and MIC report it was found that the 2:1 ratio has very good bactericidal activity in comparison to other ratios under study. It was found that ceftriaxone and sulbactam combination along with 3mg/ml of Disodium EDTA has significant (p<0.001) bactericidal activity as compared to ceftriaxone and sulbactam alone. It was concluded that the ceftriaxone +sulbactam in the ratio of 2:1 along with EDTA disodium (3 mg/ml)lowers MIC to >8 fold and possess synergy against the most ESBL producing micro organisms. The combination was found to have beneficial property against troublesome strains and might be considered as a promising therapy for severe infections to overcome resistance.