Foregut contents of 56 specimens of Callinectes ornatus collected from Mullet Bay, Bermuda, in 1981 and 1988 were examined. Foreguts which were ≥ half full contained more prey items per gut (x = 4.67) than did guts < half full ( x = 2.73). Dietary analysis was based on 2 methods: (1) the index of relative importance (IRI), which combined frequency of occurrence (FO), percentage of total biomass, and percentage of total numbers consumed, and (2) weighted points, which combined FO and estimated relative volumes of each prey item. No significant differences were revealed in relative proportions of foregut contents between males and females, or between adult and juvenile crabs. Modulus modulus, a cerithiacean gastropod mollusk, dominated the diet, accounting for 21.1 % of the total IRI. Two other cerithiaceans collectively ranked second (19.9% of total IRI). Carbonate substrate was the most frequently occurring category (51.79%) and ranked third in IRI (17.2% of total). Plant material, crustaceans, nereid polychaetes, fish, and bivalve mollusks ranked fourth through eighth in IRI. The validity of including carbonate substrate as a dietary component is discussed, as is the relative merit of the indices used in dietary analysis.