A precise and sensitive RP‐HPLC method is used to assay pharmaceutical dosage forms and bulk drugs for cefoperazone sodium (CPZ). The mobile phase for cefoperazone separation is a combination of acetonitrile and 0.05 M ammonium acetate buffer (pH 4.5) in a 70 : 30 (v/v) ratio. This was separated by using a Waters XTerra RP‐18 column (5 µm 250 × 4.6 mm internal diameter) that was working at a flow rate of 1.0 ml/min. Photodiode array detectors are able to set it at 235 nm. Based on the percentage recovery, the process produced a notable linear response ranging from 0.2 to 20 µg/ml, with a significant precision of 0.27 to 0.67% and an excellent accuracy of 99.90 to 100.02%. Because of its outstanding sensitivity, accuracy, precision, and ease of use, we highly suggest using the reversed‐phase HPLC method. Therefore, a laboratory could utilize this method for routine quality control analysis.