Chemical composition, profile and apparent amino acids digestibility (AAAD) and true amino acid digestibility (TAAD) as well as metaboilzable energy as apparent (AME) and true (TME) and those corrected for nitrogen balance (AMEn) and (TMEn) of poultry by product meal (PBPM) were determined using force feeding assay. Moreover, protein quality of PBPM was assayed using total protein efficiency (TPE). A feeding trial was also conducted utilizing roaster type chicks ( Sasso males x Golden Montazah females) to evaluate PBPM protein at approximately 40/60% of soybean meal (SBM) protein in the growing /finishing diets. There were five experimental isocaloric, isonitrogenous diets in which a control corn-SBM diet represents the positive control. In other four diets, one PBPM-diet was kept as a negative control, whilst in the other three diets, one was formulated based on true digestible methionine and lysine (TDML), or TAAD or supplemented with 0.125 g of poultryzyme® /kg diet. Each diet was fed to three replicates each containing eight chicks during days 1-98 of age. PBPM contains 59.31% CP, 0.61% methionine, 1.91% total sulpher amino acid (TSAA), 2.33% lysine, 3.71% arginine, 1.19% threonine, 0.45% tryptophan and 4121 kcal AMEn, while methionine, threonine and lysine were the 1st, 2nd and 3rd limiting amino acids, respectively. TAAD of PBPM was 89.8, 86.9, 91.8, 87.5 and 85.5% for methionine, lysine, arginine, threonine, and tryptophan respectively. There was no significant difference in total protein efficiency between SBM and PBPM. Formulating the PBPM containing – diet based on TDML improved growth compared to the positive control PBPM containing-diets, and resulted in FCR similar to that of the positive control. Poultryzyme® addition or formulating the diet containing PBPM based on TAAD significantly improved FCR compared to its negative control. Results revealed that PBPM control-diet could be fed without or with poultryzyme® with expected improvement in the economic efficiency. Carcass yield, internal organs, chemical composition and physical characteristics were neither adversely affected by PBPM, nor there were negative effects on plasma constituents and liver functions. It could be concluded that PBPM at 10.5/13.5% level in the growing diets for roster type chickens had no adverse effects on growth performance, carcass characteristics and liver functions. Keywords: chickens, amino acids, protein quality and growth performance.