Anti-Mϋllerian hormone (AMH) is a transforming growth factor family glycoprotein expressed exclusively by the granulosa cells of growing antral follicles. AMH plays an inhibitory role during initial primordial follicle growth recruitment and regulates the continued growth of large pre-antral and small antral follicles. AMH is an endocrine marker of ovarian reserve in humans, a reliable marker of the response of cows to super-ovulatory stimulation protocols, and can be used to identify which ewes should be used as donors for laparoscopic ovum pick up. This study had two primary aims; one, to determine if there is an optimum time to measure AMH relative to synchronisation of the oestrous cycle, and, two, to determine whether AMH levels differ between breeds of sheep. Suffolk (n = 19) and Merino (n = 19) ewes were used, and oestrus cyclicity was synchronised using an intravaginal progesterone insert, which was removed after 12 days. Blood samples were collected into lithium heparin coated tubes on the day of the insertion of the intravaginal progesterone insert (day 0), and again on the day of its removal (day 12). Samples were centrifuged at 1500 rpm for 15 minutes and AMH levels measured in the plasma using an ovine AMH ELISA kit (ANSH labs, Texas, USA). Data were analysed using an ANOVA (unbalanced design; Genstat 15th Edition SP2). Mean AMH levels were similar on Day 0 and Day 12 (2.61 ± 0.25 and 2.64 ± 0.25 pg/ml, respectively; P = 0.315) and for Merino and Suffolk ewes (2.55 ± 0.25 and 2.69 ± 0.25 pg/ml; P = 0.315). The current data indicates no differences in AMH levels between non-synchronised and synchronised ewes, or between breeds, suggesting it may be a useful tool with which to select donor ewes, regardless of breed, prior to commencing oestrous synchronisation.