The purpose of this study was to determine the efficiency of STAT-1 and STAT-3 proteins that exist in hepatic tissue of broilers as a basis for making synthetic STAT protein that would promote broiler growth and is safe for humans. This study used 25 male Lohman broilers. The broilers were placed in battery cages with capacity of one broiler per cage and fed twice daily (10% less than the standard feed) at 6:00 AM and 6:00 PM. At the age of 21 days, the broilers were sacrificed by cutting the esophagus, trachea, carotid artery and jugular vein, and a sample of 5 g hepatic tissue was obtained to examine the amino acid sequence of proteins STAT-1 and STAT-3 by MALDI-TOP method. Results showed that molecular weights of STAT-1 and STAT-3 were 59.3 kDa and 59.4 kDa, respectively. Identifying the amino acid structure of the STAT protein can allow for the creation of STAT synthetic protein, which is expected to prolong the action or effect of growth hormone, thus, promoting growth of broilers.