There is no information regarding the presence of platelet-derived growth factors (PDGFs) and their receptors in human ovaries. The expression of PDGF-A, -B and their two receptors, PDGFR-alpha and -beta, was investigated in ovarian samples from women/girls and from human fetuses, at the protein and mRNA levels. The samples were prepared for immunohistochemical staining for PDGF-A and -B and their two receptors and in situ hybridization for the detection of the mRNA transcripts of the receptors. Total RNA was extracted from frozen ovarian samples, and the expression of PDGF-A and -B was investigated by reverse transcription-polymerase chain reaction. The proteins for PDGF-A and -B were detected in oocytes, and in granulosa cells (GC) of 50% of the follicles from women/girls. The proteins and mRNA transcripts for the two receptors were detected in oocytes (mRNA for PDGFR-beta only in 25% of the oocytes). PDGFR-alpha mRNA was expressed in GC of a minority of the samples from women/girls, whereas PDGFR-beta protein and mRNA were identified in over 50% of the GC from this source. PDGF-A and -B transcripts were identified in all the extracts. The presence of the receptors in GC suggests that PDGFs might be involved in the activation of primordial follicles.