Nowadays, consuming dietetic oils supplements has become a common way to intake some nutrients that are not part of the diet. Omega-3 is one of the most popular dietetic supplements. Omega-3 purification is normally achieved using concentrations and distillations process, which, in some cases, transform the fatty acids into one of their esters, reducing their bioavilabilities. Conventional analytical chemistry methods to monitor quality parameters are expensive and time consuming, being not suitable for on-site analysis. . Infrared (IR) spectroscopy is an analytical technique that has been used for more than 5 decades. IR is a non-destructive technique that based on the interaction of the light and matter to obtain the physicochemical information of the matter. The application of IR coupled with multivariate techniques bring the opportunity to develop a fast and accurate models to monitor quality parameters in dietetic oils supplements.