A modern, rapid RP-HPLC-UV method was developed and validated in compliance with FDA and EMA guidelines for simultaneous quantification of 15 β-lactam antibiotics) Ampicillin, Amoxicillin, cephalexin, cefotaxime, cefoxitin, cefamandole, cephalothin, piperacillin, penicillin, oxacillin, cloxacillin, nafcillin Carbenicillin, Mezlocillin and Dicloxacillin) in pharmaceutical formulations and pure forms. The method employs Column NEUCLEODUR C-18 (4.0 mm x 100 mm, 5µm particle size), at a temperature of thirty degrees Celsius, and the mobile phase was acetonitrile and KH2PO4 using gradient elution with a total separation time of 13 minutes, a flow rate of 1.3 ml/min, at = pH 4.5 for the buffer solution and the λ max was 220 nm. The method demonstrated a linear calibration range of 0.2-20 µg/mL with coefficients of estimation of 0.9994 Recoveries were 100.4 - 90.86%. The chromatography approach in this study was applied to simultaneously determination of pharmaceutical compounds in commercial products.