Abstract The paper proposes a near infrared method able to directly and simultaneously quantify ascorbic acid and sodium ascorbate in powder blends for tableting and in vitamin C chewable tablets without any sample preparation. In the first step, calibration models for the quantification of ascorbic acid and sodium ascorbate in powder blends for tableting and subsequently in chewable vitamin C tablets (corresponding to 80-120 % active substance) were developed according to an experimental design with 2 variables and 5 levels. Then, using the best calibration models, the methods were fully validated in terms of recovery, precision and accuracy for both powder blends and vitamin C chewable tablets. The validated concentration range was 15.14-18.51 % for ascorbic acid and 12.06-14.49 % for sodium ascorbate in powder blends and 91.85-111.03 mg per tablet for ascorbic acid and 71.01-84.50 mg per tablet for sodium ascorbate in tablets. Validation results showed good precision and accuracy.