The feeding habits of Hoplobrotula armata were studied using 269 specimens collected in the coastal waters of Geomun-do, Korea. The size of the specimens ranged from 5.6-56.8 cm in total length (TL). H. armata is a canivore that consumes mainly teleosts and decapods (shrimp, crabs and hermit crabs). Its diet also includes gammarid amphipods, cephalopods, polychaetes and copepods. Smaller individuals (<20 cm TL) fed mainly on fish, shrimp and crabs. The proportion of shrimp and crabs decreased as body size increased, whereas the consumption of fish gradually increased. Fish accounted for almost the entire stomach contents of individuals (larger than 40 cm TL).