Benzoic acid analysis in curry paste samples were carried out by using high performance liquid chromatography using ultrasonic extraction. Methanol-0.05 M ammonium acetate buffer pH 4.40 in the ratio of 55:45 (%v/v) at a flow rate of 1.00 mL/min was used as the mobile phase and benzoic acid detection was performed at 226 nm using an UV-Visible detector. Under the optimum conditions, linearity of spiked samples ranged from 50 to 3,000 mg/kg. Matrix matched calibrations had determined that benzoic acid contents in southern sour, red, and green curry paste samples were 67.59, 78.62 and 72.33 mg/kg, respectively. Recoveries were obtained from 89.34 to 101.70%, 83.37 to 130.30% and 92.75 to 113.56% with R.S.D. ranged from 2.71 to 6.53%, 4.02 to 11.58% and 5.81 to 6.35%, for southern sour, red, and green curry paste samples, respectively.