Protein composition of human ovarian follicular fluid (FF) constitutes the microenvironment for oocyte development. Several proteomics studies of FF from pre-ovulatory follicles have revealed insights on oocyte maturation, however, there is a lack of knowledge on changes produced at protein levels in the FF of human small antral follicles (hSAF) related to the upcoming oocyte maturation. Using mass spectrometry-based proteomics, we evaluated the protein composition of FF that surrounds oocytes capable to reach metaphase II (MII) after IVM with the protein profile of FF that surrounds immature oocytes. The samples were collected from small antral follicles (size 6.0 ± 1.5 mm) extracted from six women, from which two or three samples were extracted. The comparison was based on both, a multivariate (sPLS-DA) and univariate analyses (t-test).