Radiocarbon dating of bone is one of the main activities of the Dating Laboratory of Lyon. Collagen, the main organic component of bone, is the material analyzed. Collagen disappears more or less quickly depending on the conditions of the soil in which bone is buried. A method requiring only a small sample of bone was devised to measure the quantity of organic material still in the bone as soon as it reaches the laboratory. It was found that, for a given site, there is a link between the quantity of organic material remaining in bone and the age of the bone. Further refinement of the test method and careful study of the soil at a site could help give the relative ages of samples from that site. -- AATA