This is the first time that the genus Dodecaceria is reported in shell galleries of the red abalone Haliotis rufescens. The worms measures up to 60-mm long with about 120 setigers and have a brown-greenish color. Previously Rozbaczylo and Carrasco (1996) mentioned the presence of this species in the shells of the gastropod molluscs Fissurella maxima and Concholepas concholepas and in the bivalve Aulacomya ater. Hernández et al. (2001) reported it in the shell of the barnacle Austromegabalanus psittacus in Concepción, Chile.