Background: In vitro maturation (IVM) is a relatively new method of assisted reproduction. The basis of this method is maturation of immature oocytes in conditions in vitro. The main advan- tage of this method over the conventional IVF/ICSI technique is that patients don’t need medications for controlled ovarian hyperstimulation and that ovarian hyperstimulation syndrome (OHSS) is avoided. The avoidance of OHSS is very important for patients with polycystic ovarian syndrome (PCOS), which have increased risk for OHSS. The IVM method is suitable for those patients with PCOS who require treatment with assisted reproductive technology (ART). There are numerous factors which influence the maturation of human oocytes in vitro such as the nature of the patients, endogenous endocrine background, treatment with go- nadotrophins and ovarian steroids, cumulus cell and granulose cell function. In spite the fact that pregnancy rates have been improved in IVM patients last years, the implantation rates stay low (10–11 %). Reports on children born after IVM showed no increased risk for congenital malformations, however permanent follow-up of this children is needed. Conclusions: IVM is a promising method of ART and offers good results for PCOS patients. Further inves- tigations are needed to improve the success of IVM method.