The present  studywas designed to evaluate the influence of supplementing different levels of L-Valine (L-Val) to low protein diet on chicks' performance, carcass characteristics , digestibility of nutrients andeconomical efficiency. A total number of 640 unsexed day old Arbor Acres meat – type chickswere assigned  randomly  into 8 equal treatments containing 80 chicks each (10 birds/ replicate). The first group (control) was fed strain recommendation of CP being 23%, 21% and 19% with 0.96, 0.88 and 0.79% digestible valine during starter, grower and finisher periods, respectively  (T1). The 2^nd group was feddiets with a 3% CPless thanthe control, being 20%, 18% and 16% and contained 0.89, 0.79 and 0.69% digestible valine level during the same growth phasesrespectively, as control (T2). Other six groups were fed low–CP diet (LPD) supplemented with 250mg, 500mg, 750mg, 1000 mg, 1250 mg and 1500 mgL-Val/kg diet, respectively. The study lasted for 38 days.  The results were as follows:1- The best  BWG and FCR during overall growth period was achieved by chicks fed the LPD supplemented with 500 mg Val/kg diet, and control group (T1) without significant differences between them.2- Valine digestibility was ranged between 91.17 to 97.03%.3-Control group achieved significantly the lowest abdominal fat percentage as compared to the other groups fed LPD either with or without valine supplementation.4- Chicks fed the LPD plus 500 mg Val/kg diet attained the highest means of economic efficiency and its relative value by 103.2% and 114.2%  as compared to those fed the recommended protein diet and LPD, respectively. In conclusion, the best level of added Val is 500 mg/kg diet for broilers fed LPDsupplemented with sufficient amount of Methionine, Lysine, Threonine which coincided with the best Val/Lys ratio during starter, grower and finisher periods. Also, it achieved an improvement in economic efficiency and growth performance of broilers.