The order Decapoda represents a species-rich group of crustaceans. Numerous economically important and morphologically diverse members of this group have been studied extensively for many decades, in part to understand their phylogeny. There are several competing hypotheses concerning relationships among the major lineages of Decapoda. Our laboratories are estimating a robust decapod phylogeny based on molecular and morphological data in an attempt to resolve relationships among major lineages. The order includes roughly 175 families and more than 15,000 described species (extant and extinct). Interpretations are complicated by the estimated 437 million years since origin of the Decapoda, with all the major lineages likely established by 325 million years ago. Constructing a molecular phylogeny across such a timescale requires markers with enough variation to infer relationships at the fine scale (at and within the family level) but which are conservative enough to refl ect deeper divergences across infraorders. Here we present a molecular phylogeny for the order Decapoda, combining nuclear and mitochondrial sequences, to investigate relationships among nine pleocyemate infraorders, one dendrobranchiate superfamily, 56 families, 113 genera, and 128 species. New and available sequence data are assembled to build the most extensive decapod phylogeny to date both in terms of taxon representation and genetic coverage. We discuss current and new hypotheses of decapod relationships and suggest a plan for the movement towards a consensus of decapod evolution.