The growth hormone of chickens affects the growth and development of chickens, egg production, body type, appetite control, reproduction, and response of body immune system. Several studies have shown that the growth hormone gene is a candidate gene for chicken economic traits. The polymorphisms of this gene can be used to improve of production, phylogenetic analysis and marker assisted selection programs. In this study, allelic polymorphism in intron 1 of growth hormone (cGH) gene in the Marandi indigenous chicken examined using PCR-RFLP technique. A total of 100 birds were selected and for detection of mutation in intron 1 of cGH gene (776 bp), the PCR products were digested by MspI restriction enzyme. The results showed that the five genotypes and three of the A1, A2 and A3 alleles with frequency of 24, 4 and 73 percent respectively, identified. The A3A3 genotype had the highest (0.50) and the lowest (0.02) frequency was found for A1A1 and A1A2 genotypes. In the total population, Shannon's information index and Fixation index 0.69 and -0.16 respectively, calculated. According to the Chi-square test, the Marandi indigenous chickens had a Hardy-Weinberg equilibrium for this locus. Considering the high polymorphism of this locus in Marandi indigenous chickens can after determining the genotype and the performance of each genotype in the production of economic traits be used as a marker in genetic selection and breeding programs to improve the economic traits associated with growth hormone.