(1) The following data are the validation of a method for the determination of vitamin B3 (also called vitamin PP or niacin) in dairy products. It is based on measuring nicotinamide (natural vitamer). The analytical procedure concerns milks which typical concentrations vary between 0.6 and 1.0 mg/L, according to the product nature. Due to thermal treatments or authorized fortification, the marketed products rather stand between 0.4 and 2 mg/L. In order to