Aim This study sought to evaluate the endogenous female sex hormones secretion abnormality in postmenopausal women with coronary artery disease(CAD)and its influence on nitric oxide synthesis. Methods We assessed the concentration of serum female hormones,estradiol(E₂)and progesterone(P)by using radioimmunoassay and determined serum NO(Nitrite/Nitrate) and the activity of NO synthetic enzyme(NOS)by colorimetry in 100 postmenopausal women with coronary artery disease and 100 healthy postmenopausal women who were enrolled in this study. Results Postmenopausal women with coronary artery disease had significantly lower E₂,higher P levels(121±32 pmol/L vs 156.2±30.6 pmol/L,5.67±1.6 nmol/L vs 3.14±1.1 nmol/L respectively)and lower E₂/P ratio(52.4±26.5 vs 127.9±37.8) than healthy postmenopausal women.The serum NO level and NOS activity were lower in women with CAD than in healthy women.The serum E₂ level and E₂/P ratio were positive correlative with NO level and NOS activity,whereas,the serum P level was passive relative with NO level and NOS activity. Conclusions Compared with healthy postmenopausal women,women with CAD have lower estrogen,higher progesterone levels and significantly lower E₂/P ratio.This endogenous female hormones imbalance do adverse effect on the vascular endothelial function.