Research question: What are the effects of long-term androgen priming in Bologna criteria poor ovarian reserve (POR) patients undergoing IVF? Design: This open-label pilot study was conducted at IVFMD, My Duc Hospital, Ho Chi Minh City, Vietnam. It included consecutive patients aged 18–41 years who fulfilled Bologna criteria for POR undergoing intra-ovarian androgen priming and ultra-long down-regulation with a gonadotrophin-releasing hormone agonist (GnRHa), followed by stimulation with gonadotrophins and GnRH antagonist co-treatment for IVF (n = 30). Priming consisted of low-dose recombinant human chorionic gonadotrophin (rHCG) 260 IU every second day plus letrozole 2.5 mg/day, both for 8 weeks; priming stopped on the first day of ovarian stimulation. The primary endpoint was serum anti-Müllerian hormone (AMH) concentration 8 weeks after priming. Secondary endpoints included antral follicle count (AFC) (2–10 mm), serum human chorionic gonadotrophin (HCG), testosterone and progesterone levels. Results: Circulating testosterone, progesterone, oestradiol and HCG levels remained unchanged during androgen priming; the mean AMH level decreased steadily from 0.49 ng/ml (baseline) to 0.33 ng/ml (8 weeks). AFC was 4–5 throughout the study. A mean of 1.1 ± 0.9 good transferable embryos were obtained; embryo transfer was performed in 15 patients; no ongoing pregnancies were obtained. Conclusions: Long-term intra-ovarian androgen priming in the current set-up had no significant effect on hormone levels, AFC and recruitable follicles after ovarian stimulation in Bologna POR patients undergoing IVF. Further studies are needed to explore other androgen priming protocols and the clinical value of priming regimens in IVF.