International audience This paper presents the results of the excavation of inhumation burials recently unearthed in the township area of Sion (canton Valais, Switzerland) and dated between the 4th and the 1st century BC. These data provide additional information concerning the funerary practices of local prehistoric populations. The corpus consists of sixty graves to which have been added weapons recovered in earlier times from La Tène graves in the region ; included are fifteen warrior graves, most equipped with a sword, a spear and a shield, allowing the detailed study of scabbard types, more particularly those of the Ludwigshafen group as well as an "asymmetrical" scabbard (with the front plate shorter than the back plate at the mouth). Inhumation is the rule. The presence of a wooden coffin is systematic (59 of 60 analysed burials). Two thirds of the wooden containers are longitudinally-split hollowed-out tree trunks covered normally by a wooden plate but in several cases by a second longitudinally-split trunk. The study of both textile remains and ornaments - in particular brooches - permits a consideration of female costume ; in the warrior graves, the deceased are enveloped in animal skin shrouds, while the weapons are often wrapped in fabrics. The presence of anklets, specific to this alpine region, allows the fairly precise delimitation of a territory corresponding to the civitas of the Seduni, attested in ancient sources.