Specimens of Callionymus beniteguri (n=89) were collected from the waters off the coast of Taean, Korea, between April 2008 and January 2009, and their feeding behavior was observed. C. beniteguri (4.0-15.5 cm SL) was found to be a bottom-feeding carnivore that primarily preyed on gammarid amphipods, and secondarily consumed polychaetes but also ingested bivalves, shrimps, cumaceans, and sea urchins. Six additional minor prey groups also contributed to its diet, but the index of relative importance (IRI) for these groups was relatively low (<1.0). C. beniteguri exhibited size-related dietary changes. Small individuals (<10 cm SL) mainly consumed amphipods. As fish size increased, amphipods tended to decline in IRI, while the contributions of bivalves, sea urchins, and polychaetes became more important.