We studied the feeding dynamics of young-of-year (YOY) brown trout (Salmo trutta) inhabiting stream-margin habitat of a mountain stream during August and September. We found invertebrates in fish stomachs throughout 24-h sampling periods. The abundance of items in stomachs increased with the density of drifting invertebrates after dark. Composition of stomach contents and composition of drifting invertebrate samples were related, but Ephemeroptera larvae had positive electivity indices more frequently than other taxa. The mean lengths of invertebrates in stomachs were greater than those in samples of drifting invertebrates.