Preservatives are added to beverage formulations to prevent spoilage. In our study, an efficient method for the quantification of sodium benzoate (BEN) and potassium sorbate (SOR) in beverages was applied using reversed-phase high-performance liquid chromatography (RP-HPLC) with diode array detection (DAD). Ninety-seven samples were collected in two categories (carbonated and non-carbonated drinks) from the Isfahan market, Iran. Under optimal conditions, the retention times for determining the preservatives were less than 5 minutes. Among all samples, 6.1 % and 5.1 % of non-carbonated drinks contained BEN and SOR, respectively, which are not allowed according to Iranian standards. Additionally, all concentrations of BEN and SOR were lower than the general standards of the Iran National Standards Organization (600 mg·L⁻¹).