Atlantic salmon (Salmo salar L.) (280 g, initial weight) were fed for 60 days on diets in which fishmeal was substituted with graded levels of extracted soybean meal (SBM) comprising 0%, 10%, 15%, 20%, 25% or 35% of the total protein. The effects on feed intake, growth, feed conversion, apparent digestibility and utilisation of macronutrients and energy, pathohistological response of the distal intestine (DI), activities of digestive enzymes in the mid and distal intestinal mucosa, and faecal trypsin and plasma insulin concentrations were studied. A negative, dose-dependent effect of SBM was observed on nearly all performance parameters with the notable exception of feed intake. The results suggest that caution should be exercised in the use of even low levels of extracted SBM in salmon feeds (Krogdahl et al. 2003).