The complete sequence of the 18S rRNA gene of Philyra pisum was determined by using PCR cloning and Taq sequencing. The sequence was compared with those known from other crustaceans. The decapods (Oedignathus inermis, Pugettia quadridens, Philyra pisum) were distinguished from the other crustaceans (Artemia salina, Bosmina longirostris, Diastylis sp.) by longer sequences (17-41 bp) in the V9 region.