ABSTRACTA stomach flushing technique is described which has been used for over a year, both in the laboratory and in the field. It is reliable, quick and relatively easy to perform and has been applied to juvenile Atlantic salmon (Salmo salarL.) and brown trout (S. truttaL.). The only limitation on its use was that fish<4 cm in length were considered too small to flush. Experiments carried out show that the technique removes 98.9% of the stomach contents from the fish and has very little effect on subsequent survival (99.3%) and condition. It is suggested that this technique is an improvement on previous designs.