The objective of this investigation was to verify the structural characteristics of preantral follicles (PAF) of cat ovarian tissue after cryopreservation in 1.5 M glycerol or ethylene glycol, using a slow-freezing procedure. Ovaries (n = 10) from domestic cats were divided into fragments. One fragment was immediately preserved for classical histology (fresh control), and additional fragments were immersed in minimum essential medium plus 10% bovine fetal serum (MEM+BFS), or MEM+BFS supplemented with 1.5 M glycerol or ethylene glycol. The samples were frozen and plunged into liquid nitrogen. After 1 wk, the samples were thawed. A total of 600 PAF were evaluated. In the fresh control, there were 71.3% normal PAF. After thawing, the rates of normal PAF were 26.0, 39.3 and 58.0% for samples without cryoprotectant or with glycerol or ethylene glycol, respectively. We concluded that ethylene glycol was useful for the cryopreservation of feline PAF in situ.