A major side-effect of controlled ovarian hyperstimulation (COH) in patients with polycystic ovary or polycystic ovarian syndrome (PCOS) is the risk of ovarian hyperstimulation syndrome (OHSS). In-vitro maturation (IVM) of immature oocytes represents a potential alternative for the fertility treatment of these patients. Recently applications of FSH (hMG) or hCG priming have been used before immature oocyte retrieval to improve the success rate of IVM procedures. Although it is still controversial hCG priming before oocyte retrieval seems beneficial in terms of easier oocyte retrieval easier oocyte identification under stereomicroscope maturation competence and may increase the harvest of in vivo mature oocytes. Recently new approaches attempted to improve the IVM program such as extending hCG stimulation or optimal hCG timing before immature oocyte retrieval. Therefore as a first option hCG-priming IVM treatment can be offered to women with PCO(S) instead of conventional IVF treatment with ovarian stimulation. In this session I would like to introduce you to the recent progress of IVM cycles after hCG priming.