The use of alternative protein sources in ruminant diets is of interest because of restrictions on the use of animal proteins, loss of nitrogen (N) compounds to the environment and efforts to reduce costs of systems. A problem of some protein-rich-ingredients is that they degrade rapidly in the rumen. The use of tannins has been proposed as a means of reducing the extensive dietary protein degradation in the rumen. However, condensed tannins have been reported to exert detrimental effects on gut microflora and on the gastrointestinal tract, and they can affect post-rumen digestion. The two experiments reported here aimed to study the influence of quebracho tannins (QTs) on ruminal degradation of peas (Pisum sativum) and sweet lupins (Lupinus luteus), and to investigate the effect of QTs on postrumen digestibility of these feeds using a poultry model.