This study was conducted to identify genotypes and evaluate the effect of polymorphisms in Growth Hormone (GH), Prolactin (PRL), Bone Morphogenetic Protein Receptor-Type IB (BMPR-1B) and Melatonin Receptor-Type 1C (MTNR-1C) gene son egg production of Japanese quail during 5-month laying period. PCR-RFLP and PCR-SSCP methods were used to determine the genotype of all genes. It was shown that at loci C2161G (PRL) and G294A(MTNR-1C) the genotype was conserved with only one allele (either C or A) was found in the population, respectively. For the A237B (GH) and A290T (BMPR-1B) mutations, two alleles were detected to formulate three genotypes at each locus. In addition, the 24-bp difference of two genotype patterns provided an Indel-358 mutation in Prolactin gene while three alleles were identified at locus A459TC (MTNR-1C). In general, the polymorphic sites did not affect egg production with the exception of the A459TC locus (P=0.002), where quail carrying AA and CC genotypes provided highest egg number (115.6-116.6 eggs/quail). This single nucleotide polymorphism (SNP) is suggested to apply in other populations and it could be considered as a potential marker for egg production to enhance breeding programs in Japanese quail.