An examination of the diet of the common coral-reef gastropod Vasum turbinellus, based upon the gut content analysis of 280 specimens from various localities, shows a diet consisting of approximately 50% polychaete annelids and 50% sipunculans. Chaetopterid polychaetes form about 20% of the diet at most places but species of Eunicidae and Terebellidae are also common prey items. Vasum rhinoceros, an East African species, also eats polychaetes and sipunculans, and two individuals of the large Vasum ceramicum had been feeding upon eunicid polychaetes. Amongst those gaatropods with which it coexists Vasum turbinellus overlaps in diet with species of Mitridae and Drupa lobata and D. grossularia, which are sipunculan specialists, and to a lesser extent with species of Conus and Drupa morum which feed upon polychactes, particularly from the Eunicidae and Nereididae. No other common shallow-water gastropods seem to feed regularly upon chaetopterid polychactes. Limited evidence from other members of the Vasidae would suggest a polychaete or a mixed polychaete/sipunculan diet.