In vitro oocyte maturation (IVM) is a mild-approach assisted reproductive technology (ART). Because of its simplicity, the more favorable financial implications (reduced cost) for patients, and the lower health risk profile of IVM compared to controlled ovarian stimulation (COS) in polycystic ovary syndrome (PCOS) patients, the use of IVM in selected patients may gain increasing interest. Besides its application in patients with polycystic ovaries, IVM technology may have a role in fertility preservation, where young girls and adult women are facing infertility due to gonadotoxic chemotherapeutic treatment.