Abstract: The objective of this study was to investigate the polymorphism of the melatonin receptor gene(MTNR1B) and its association with laying traits in Wenchang chickens. Single nucleotide polymorphisms (SNPs) were detected in 5′ regulatory region, exon 1 and exon 2 of MTNR1B by direct sequencing, and the association of SNPs with laying traits was also analyzed. The results showed that no base mutations or deletions were detected in exon 1 and exon 2, while 15 SNP loci were found in 5′ regulatory region. Dominance effects at -778 locus were 2.3 and 6.2 eggs for egg number from 22 to 31weekold and total egg number until 46weekold, respectively. At -216 locus For egg number from 32 to 46weekold and total egg number until 46weekold, additive effects were 2.5 and 3.2 eggs, respectively, and dominance effects were 3.5 and 6.8 eggs, respectively. Hens with the haplotype AA had the least egg number from 32 to 46weekold and egg number until 46weekold and hens with the haplotype GC had the earliest age at first laying. Hens with combined genotype AC/GA had the most egg number during the periods from 22 to 31weekold, 32 to 46weekold. In conclusion, exons of MTNR1B are highly conservative, while SNPs in 5′ regulatory region are maybe as candidate markers for laying traits.