Scanning Electron Microscopy (SEM) allows a precise identification of the surface of the structures. When associated with the cryofracture technique, it allows a more detailed analysis, since the samples have their internal structures exposed. Thus, the protocol and results of SEM associated with cryofracture in Astyanax lacustris ovaries are presented here in order to characterize the external and internal structure of the oocytes. A. lacustris ovaries were collected, prefixed in 4% paraformaldehyde, fixed in osmium tetroxide (2% OsO ₄) at 4 ºC and kept overnight in phosphate-buffered saline. The samples were washed, immersed in DMSO at different concentrations, followed by their fracture in 50% DMSO cooled by liquid N ₂ and then immersed in 50% DMSO until returning to room temperature. The fractured samples were taken for maceration in 1% osmium, in a shaker for 15 hours. Afterwards, the samples were post-fixed in 2% OsO ₄ for 2 hours at 4 ºC, dehydrated in an increasing ethanol series and taken to the critical point apparatus Balzers CPD-030 using liquid CO ₂. This was followed by the assembly of the blocks and the metallization of the sample with gold ions, with the analyzes carried out in a Scanning Electron Microscope Jeol JSM-7401F 5V. It was found that the cryofracture technique provided images with greater internal detail of the oocytes. Some specific characteristics of fish oogenesis could only be observed using this new technique, with emphasis on the oocyte envelope, the micropyle and the zona pellucida, as well as the connective membrane associated with the ovarian structures.