Le Guildo castle is situated on a rocky outcrop overlooking the upper estuary of the River Arguenon. Since 1995, excavations hâve been carriedout in association with the présentation of the site to the public. The médiéval castle suffered numerous transformations, due mainly to installation of artillery during the 16th century. The consolidation of the remparts (the earthfill ofthe lower rooms) contained a homogeneous but varied series of artefacts. Three archaeological contexts were selected for artefact analysis, the choice being based on the quality, homogeneity and chronological precision (due to the présence of coins). The non-ceramic artefacts (glass and metals) confirm the chronology by comparison with other excavated contexts in northern France. The study of ceramics is based on a technical and typological approach. From thisfirst catalogue of artefacts in use during this period in Brittany, a discussion is engaged concerning the commercial links and the supply of this coastal site.