In 1981, Kitchell et al. envisaged a net energy maximization model that can rank different prey according to their preferences. Several workers tested the model both in experimental studies and in fossil records. In the present endeavor we have tried to analyze the nature, from a cost-benefit perspective, of naticid prédation on two Recent prey bivalve species Mactra luzonica Reeve, 1854, and Donax scortum Linnaeus, 1758, collected from eastern coast of India. The results have broadly supported the theoretical cost-benefit curve of Kitchell et al. (1981). While Mactra luzonica was thoroughly preyed upon regardless of body size, predation on Donax scortum significantly decreased after prey body size exceeds 3 cm. This is explained on the basis of a change in mode of living of the prey during late ontogeny, Other factors like prey availability, prey ornamentation, consumption rate, and presence of secondary predators that may constrain the model, have been discussed.