Effect of background tenderness factors and actomyosin tenderness factors on the tenderness of poultry meat at various physiological ages were observed. The shear values of male meat are show lower than that of female and the shear values is apt to decrease during postmortem storage, regardless of physiological maturity and sex. Actomyosin tenderness factors have no effect on the tenderness after death immediately but affect the tenderness during postmortem storage largely, regardless of physiological maturity. However, background tenderness factors have greater influence on the tenderness attributed by the physiological maturity remarkably in all groups.