A simple, specific, precise, and efficient method for the Simultaneous estimation of Sulbactam and Durlobactam in pure and pharmaceutical dosage forms by a Reverse Phase-High Performance Liquid Chromatography method is developed and validated. Selected mobile phase were in a combination of Acetonitrile and Acetate buffer (pH-4.3) (35:65% v/v). Optimized column is a Develosil C18 (4.6mm×250mm) 5µm particle size and at a flow rate of 1.0mL/min with detection wavelength at 238nm for Sulbactam and Durlobactam. In our study, the validation of analytical method for determination of Sulbactam and Durlobactam in pure and pharmaceutical dosage forms was performed in accordance the parameters including-system suitability, specificity, linearity of response, accuracy, precision (reproducibility & repeatability), robustness (change of wave length±2 nm). The method is validated according to ICH guidelines. In RP-HPLC method, the calibration graphs were linear in the concentration range of 10-30μg/ml for Sulbactam and 30-90μg/ml for Durlobactam with percentage recoveries are within the limits. The results obtained by RP-HPLC methods are rapid, accurate and precise. Therefore, proposed method can be used for routine analysis of Sulbactam and Durlobactam in the pure form as well as in combined pharmaceutical dosage form. Keywords: Sulbactam and Durlobactam, HPLC, Method Development, Validation.