The Meliphagoidea comprises the largest radiation of Australasian passerines. Here we present the first detailed molecular phylogenetic analysis of its families and genera, particularly the Acanthizidae, using sequences from nine gene regions including both mitochondrial and nuclear DNA. Our results support some suggested relationships but challenge other groupings, particularly in Meliphagidae and Acanthizidae. Maluridae is sister to all other members of the superfamily. With appropriate taxon sampling and multilocus data, we provide the first strong molecular evidence supporting earlier recognition of bristle-birds, Dasyornis, as a separate family, Dasyornithidae. We further clarify its position as sister to Acanthizidae + Pardalotidae + Meliphagidae. Pardalotidae is sister to Acanthizidae, and thus its retention as a separate family is arbitrary. The meliphagid genus Lichenostomus is polyphyletic. We find no support for the current subfamily structure within Acanthizidae but recognise a clade that includes members of the subfamily Sericornithinae excluding Oreoscopus and Acanthornis. Subfamily Acanthizinae is para-phyletic. Surprisingly, the Tasmanian island endemic Acanthornis magna of mesic habitats is sister to the Aphelocephala whitefaces of mainland Australian xeric zones. This is one of several unexpected alignments of taxa as sisters that probably reflects the age of the Meliphagoidea. We find no evidence for separate radiations of New Guinean and Australian members of the Meliphagoidea. (C) 2010 Elsevier Inc. All rights reserved.