The aim of the present study was to investigate a possible correlation between decreased androgen levels and female sexual function index ( FSFI) in women with low libido and compare these findings with normal age-matched subjects. In total, 20 premenopausal women with low libido ( mean age 36.7; range 24 - 51 y) and 20 postmenopausal women with low libido ( mean age 54; 45 - 70 y), and 20 premenopausal healthy women ( mean age 32.2; range 21 - 51 y) and 20 postmenopausal healthy women ( mean age 53.5; range 48 - 60 y) as controls were enrolled in the current study. Women with low libido had symptoms for at least 6 months and were in stable relationships. All premenopausal patients had regular menstrual cycles and all postmenopausal patients and controls were on estrogen replacement therapy. None of the patients were taking birth control pills, corticosteroids or had a history of chronic medical illnesses. All completed the FSFI and Beck's Depression Inventory (BDI) questionnaires. Hormones measured included: cortisol; T3, T4 and TSH; estradiol; total and free testosterone; dehydroepiandrosterone sulfate ( DHEA-S); sex hormone binding globulin ( SHBG). We performed statistical analysis by parametric and nonparametric comparisons and correlations, as appropriate. We found significant differences between the women with low libido and the controls in total testosterone, free testosterone and DHEA-S levels and full-scale FSFI score for both pre- and postmenopausal women ( P<0.05). In addition, decreased total testosterone, free testosterone and DHEA-S levels positively correlated with full-scale FSFI score and FSFI-desire, FSFI-arousal, FSFI-lubrication and FSFI-orgasm scores ( P<0.05). Our data suggest that women with low libido have lower androgen levels compared to age- matched normal control groups and their decreased androgen levels correlate positively with female sexual function index domains.