An experiment was carried out 350 unsexed chicks of a commercial broiler breed taken from a hatchery nearby the farm of the experiment in the city of Hama, Syria. The chicks were collected directly after the hatching and chicks were distributed into five groups of each 70 chicks. The chicks were fed in all groups for a week on diet supply the nutritional needs of chicks according to the American Tables of feed (NRC 1994) and by 1.20% lysine, 0.52% methionine, but has increased the ratio of lysine to diet in each of the second and third groups to 1.45%, 1.70% on respectively, have also been increasing the ratio of methionine to diet in each of the fourth and fifth groups to 0.75%, 1.00% on respectively, and were considered the first  group as a Control. After 7 days the five groups chicks were fed on the broiler pellet diet until the age of 42 days. The results showed the importance of adding free lysine to the diet after hatching directly on the average live weight at the end of the first week, the differences were significant (P ≤ 0.05) between the chicks of the third group which fed on diet containing highLevel of lysine 1.70% compared to chicks of the first group which fed on diet containing 1.2% lysine, 0.52% methionine compatible with (NRC, 1994). While no significant differences were noticed between average live weight of all groups at the end of the experiment.