The late Roman (4th century AD) archaeological materials from Arlanpe cave (Lemoa, Bizkaia) are presented in this paper. They are shards of Samian ware and Roman common pottery, glass fragments, metallic objects, animal remains, etc., which were found inside two pits dug into the ground of the cavity. Both of these structures are interpreted as “offering pits” related to some kind of magical-religious ritual of pagan origin.