Ascorbic acid is a vitamin of nutritional importance due to its role as a cofactor in several physiological processes and as an antioxidant. Due to the convenience of modern life, the consumer market has shown an increasing interest in consuming commercial products. The concentration of vitamin C present in fruit juices is  sually reported by the manufacturer on the label. The objective of this study was to quantify and validate the ascorbic acid method by High Performance Liquid  hromatography (HPLC) in commercialized orange juices. Three brands were evaluated. The analytical curve of aqueous solutions of L-ascorbic acid was obtained at concentrations between 50 and 800 mg.L-1. The samples were treated in Sep-Pak C18 and a 0.45 μm filter membrane. The identification and quantification of ascorbic acid were performed in a HPLC system, using a UV-Visible detector at 254 nm. The mobile phase used was 0.2 M phosphate buffer, pH 2.4, and the  olumn used was a Hichrom 5 C18 (15 cm x 4.6 mm). Due to its high sensitivity, the method was linear (r2 = 0.9956) and accurate (CV% ≤ 1.82%). It was observed that the method is adequate to separate the peak of the compound studied, proving the specificity and selectivity of the method. The three products analyzed showed significant results for ascorbic acid (21.94 mg.100-1 (brand A), 27.19 mg.100-1 (brand B), and 86.69 mg.100-1 (brand C). Based on ANVISA legislation, the vitamin C levels evaluated for brands A and B did not agree with those declared in the nutritional information on the label. Therefore, based on the results, it is concluded that the method adopted to identify and quantify ascorbic acid in commercial orange juice, through HPLC-UV-Visible, proved to be appropriate, providing more information to the consumer about the amount of vitamin C present in the juice.