The development of rapid analytical methods for diet authentication and quality assessments in animal products is under active investigation. We assessed the ability of visible spectroscopy to distinguish pasture-fed (P) from stall concentrate-fed (S) lamb carcasses using a large database totalling 1054 (418 P and 636 S) male lambs from three sheep breeds, i.e. 148 P and 258 S Romane breed, 102 P and 92 S Ile-de-France breed, and 168 P and 286 S Limousine breed lambs. The reflectance spectrum of perirenal fat was measured 24 h postmortem at wavelengths between 400 and 700 nm using a portable spectrophotometer. We quantified light absorption by carotenoids in the 450-510 nm area (method 1, M1) and performed a multivariate analysis over the full set of reflectance data (method 2, M2). Using M1, the proportion of correctly-classified S lambs was 100%, 95.8% and 93.5% in Romane, Limousine and Ile-de-France breeds, respectively, while the proportion of correctly-classified P lambs was 87.2%, 81.5% and 66.7% in Romane, Limousine and Ile-de-France breeds, respectively. Using M2, the proportion of correctly-classified S lambs was 99.6%, 99.6% and 97.9% in Romane, Limousine and Ile-de-France breeds, respectively, while the proportion of correctly-classified P lambs was 89.9%, 85.7% and 92.2% in Romane, Limousine and Ile-de- France breeds, respectively.