We sequenced approximately 2,000 nucleotides of the 18S ribosomal DNA gene to test previous morphological hypotheses concerning family and superfamily relationships within the Anomura. Twelve new sequences from the superfamilies Galatheoidea, Paguroidea, Hippoidea (all Anomura), and Callianassoidea (Thalassinidea) were generated, and these were combined with three previously published sequences from GenBank to estimate phylogenetic relationships among these taxa. Our results show a clear separation of the Aeglidae from the other galatheoid families, which form a sister group with the Paguroidea. Within the Galatheoidea, chirostylids and porcellanids are sister groups. Hippoidea was revealed as the most basal taxon within the anomurans.