Introduction: The main producer of "foie gras" is France. Foie gras is rich in lipids that are responsible for its organoleptic qualities. Too much fat loss during the cooking process is a major problem in the industry of foie gras. One of the main issues is to classify the foie gras in function of their technological yield (TY) before cooking them. The TY must be greater than 70% [1]. The TY is strongly correlated to the liver weight (LW) [2,3]. Thus, the study aims at identifying biomarkers specific to TY with non-invasive biomarkers in duck. 1H-NMR (nuclear magnetic resonance of the proton) analyses were performed on liver of male mule ducks at different time points during the overfeeding period to identify liver biomarkers of foie gras qualities. Material and Methods: The experimental designed is clearly described in [2]. Briefly 64 mule ducks were overfed during 6 to 12 days. Plasmas and livers were sampled every two days. The LW and TY were measured. 1H-NMR spectra of plasma were acquired on NMR 600 MHz Bruker Avance III HD. The spectra were transformed into a table of 720 buckets with WorkFlow4Metabolomics [3] and into a table of 80 metabolites with ASICS package of R [4]. Then PLS regressions were performed with SIMCA-P+ software to identify the biomarkers to LW and to TY, so as to focus on the biomarkers specific to TY. Results: The PLS models of LW and TY only contained one latent variable that enabled to separate the samples in function of LW or TY. We identified 14 biomarkers of LW and 13 biomarkers of TY. Nine biomarkers were common to LW and TY (alanine, allantoin, glucose, glyceric acid, glycogen, lactate, maltose, taurine and threonine), five were specific to LW (arginine, glucuronic acid, glycerophosphocholine, malic acid and trasn-4-hydroxyproline) and four were specific to TY (creatine, ethanolamine, glutamic acid and guanidinoacetic acid). Conclusions: It is the first study of biomarkers of foie gras quality with large approach. To complete this study, we also studied plasmatic biomarkers of foie gras quality.