Occurrence of genus Rangifer in western Europe can first be attested for the Middle Pleistocene. Scattered remains were discovered in deposits of early Middle Pleistocene in Germany and England but the most important collections for that period are at the Caune de l’Arago (Tautavel, France). The material comes from deposits correlated with MIS 14 and 12. These fossil populations are compared to other faunal assemblages from the Late Pleistocene of southwestern France, located at the reindeer southern distributional boundary. The osteological study highlights the broad similarities in the bone morphologies of the Caune de l’Arago populations compared to the later’s, confirming the specific assignment to Rangifer tarandus. Only the distal parts of the legs (metapodial III-IV and phalanx) show morphological differences. On a metric point of view, the populations of the Caune de l’Arago are characterized by a 5 to 10% larger bone size, compared to Late Pleistocene populations of the same structure (sex ratio, age). Palaeontologicaly, the results indicate a general pattern of anagenetic evolution with ecotypic variations of body size, similar to patterns found in other ungulates. The palaeoecological study supports hypothesis of i) climatic variations between Unit I and III at the Caune de l’Arago and ii) different locomotive behaviours between Middle and Late Pleistocene reindeer populations.