three assays were carried out to evaluate the nutritive value of the barnyardgrass seeds (echnochloa spp.) for poultry. in the first assay, twelve adult cockerels were used to determine the true metabolizable energy value corrected by nitrogen retained (tmen), using the forced fed method. in this assay six cockerels were forced fed 30 g of the feed and six cockerels were fastened to determinate metabolic and endogenous losses. in the second assay, twelve cecectomized cockerels were used to determine the true digestibility coefficients of the amino acids in the tested feed, using the same metodology. to determinate the apparent metabolizable energy corrected by nitrogen retained (amen) in the thirth assay, the total excreta collection method was used, with 80 growing chicks of commercial strain. the barnyardgrass seed was included in the proportion of 25 percent of the reference diet, which contained 20% cp and 3000 kcal of the me/kg. the reference and test diets were fed to four replicates of ten birds each. the energy values determined were 1813 kcal amen and 1976 kcal of the tmen/kg as fed. the true digestibility coefficients of the essential and non essential amino acids were, in average, 78.2 % and 78.3 %, respectively. the threonine and the lysine shown lower digestibility (65.8 and 67.2%, respectively) and the phenilalanine (86.4%) follow by the methionine (86.0%) presented higher values among essential amino acids. the tyrosine (90.5%) and cystine (56.3%) presented higher and lower digestibility coefficients, respectively, among the non essential amino acids.