Female fertility is critically influenced by two events affecting oocytes during meiotic prophase progression: meiotic recombination between homologous chromosomes; and a major oocyte loss. It is technically challenging to examine these events, which take place in fetal and neonatal ovaries in mammals. Here, we describe a protocol for the preparation of dissociated ovarian cells and their spread onto histology slides. These preparations are suitable for cytogenetic, quantitative, and FISH analyses.