The apparent ileal protein and amino acid digestibility was determined in legume seeds by in vivo and in vitro procedures. For both estimations 12 semisynthetic diets containing 3 varietes of faba bean, 3 varietes of pea and 6 varietes of different lupin species were used. For in vivo determinations cannulated pigs were used and in vitro analyses were performed as described by Boisen and Fernandez (1995). The relationship between in vitro predicted and in vivo values of protein digestibility was close (r² = 0.90). The higest correlation between in vitro predicted and in vivo values of amino acid digestibility was found for cystine and methionine (r² = 0.94 and 0.89, respectively). The lower correlation was obtained for lysine (r² = 0.76) and poor correlation for threonine (r² = 0.43). It was possible to predict with satisfactory precision the apparent ileal digestibility of protein, cystine and methionine in legume seeds using in vitro technique.