Prior to large studies in breast cancer patients, we have sought to establish the normal range of a potential serum biomarker, Amphiregulin, in healthy women and to determine whether sampling during the menstrual cycle influences the detected Amphiregulin levels.Serum Amphiregulin levels were quantified using a commercially available ELISA in 85 normal female donors.The range of circulating Amphiregulin was 0–4467pg/mL. The majority of women had no detectable circulating Amphiregulin (n=54), and only five women had levels exceeding 500pg/mL. Serum Amphiregulin levels did not vary significantly during the menstrual cycle (n=7 women).Detection of circulating Amphiregulin in a significant minority of healthy women suggests that it may not have the specificity necessary for a population screening tool; however its potential utility for monitoring response to treatment or disease progression should be examined in breast cancer cases.