There is an increasing consumer demand for robust analytical tools for objective authentication of the processing practices in food production chains, in particular for animal products. The aim of this work was to develop an authentication tool of grass feeding in lambs by analysing the volatile fraction of their adipose tissues. The animals were raised under experimental conditions allowing a strict control of feeding. The perirenal, caudal sub-cutaneous, an heart fat tissues were analysed by Dynamic Headspace - Gas Chromatography - Mass Spectrometry (DH-GC-MS). The analytical signal was stabilized and the drifts were corrected by using chemometrics tools. In addition to litterature data, all the experimental rearing systems used in this work allowed to reveal 19 particularely robust and generic volatile tracers of pasture diet. This work evidenced the feasibility of the authentication of feeding practices of lambs fed alternate diets. It also reinforces the ability of procedures of analytical signal treatment like instrumental drifts correction and ratios of variables to improved the discrimination power of authentication models.