Previous analyses of phylogenetic relationships within Sabellida have indicated that Serpulidae may be nested within Sabellidae, thus making Sabellidae paraphyletic. However, no DNA sequences of the one of the two sabellid subfamilies, Fabriciinae, have ever been published and the overall taxon sampling to assess the relationships of sabellids and serpulids has been poor. We further investigate this issue with Maximum Likelihood, Bayesian and Maximum Parsimony and analyses of 18S rRNA, 28S rRNA, and Histone H3 for thirty-two terminals (15 sabellids, 11 serpulids, 1 sabellariid, 1 terebellid, 1 siboglinid, and 1 oweniid) with rooting using the terebellid. The analysis of sequences under all three methods strongly supports the monophyly of a Serpulidae-Sabellidae clade, but with Serpulidae nested within the traditional Sabellidae as the sister group to Fabriciinae. We propose that instead of including Serpulidae in Sabellidae, Serpulidae should be left as a family-ranked taxon and that Fabriciinae be removed from Sabellidae and elevated to family rank as Fabriciidae. The revised Sabellidae thus equals the previous subfamily Sabellinae.