A 5-gene bivalve phylogeny includes the largest sampling to date with 84% families represented. This study populates the bivalve ToL by placing many genera into a clear phylogenetic context. Almost 20% bivalve families are not monophyletic. Plebidonax deltoides is not a member of Donacidae; major revision of Tellinoidea is required. Cementation in Cleidothaerus and Myochama may have had a single origin.