Matrix metalloproteinases (MMP) are key enzymes involved in cell and tissue remodeling during ovarian follicle development and ovulation. The control of MMP9 transcription in ovarian follicles occurs through a core promoter region (-2,400 to -1,700 bp). The aim of this study was to screen genetic variations in the core promoter region and examine MMP9 transcription regulation and reproduction performance. A single cytosine deletion/insertion polymorphism was found at -1954 $C^+/C^-$. Genetic association analysis indicated significant correlation between the deletion genotype ($C^-$) with total egg numbers at 28 weeks (p = 0.031). Furthermore, luciferase-reporter assay showed the deletion genotype ($C^-$) had significantly lower promoter activity than the insertion genotype ($C^+$) in primary granulosa cells (p<0.01). Therefore, the identified polymorphism could be used for marker-assisted selection to improve chicken laying performance.