Reproductive biotechnologies such as cooling and freezing semen are employed in order to obtain genetic enhancement in domestic animal breeds. However, cryopreservation of donkey semen, as in several other domestic mammalian species, has not yet reached a standard procedure that provides satisfactory and repeatable results, as in bulls. Despite there are over 43 million donkeys worldwide, there are only few studies about donkey semen preservation. The aim of this study was to evaluate the predictive potential of hypo-osmotic test and the supra vital staining in raw semen to be used as indicators for donkey semen freezability. Ejaculates were collected twice per week from 10 fertile donkey stallions. Volume, appearance (color and density), concentration, total motility, morphology, sperm viability (supra vital staining - eosin-nigrosin-EN) and plasma membrane integrity (hypo-osmotic swelling test - HOST) were evaluated in raw semen. After dilution the samples were centrifugated and sperm pellets were resuspended in a freezing extender to a concentration of 50 x 10(6) cells/mL. Aliquots were packed into 0.5 mL straws and placed in the refrigerator (5 degrees C) for 20 min. Subsequently these straws were kept above liquid nitrogen for 20 min, then plunged into nitrogen and stored in a holding tank. Post-thaw analyzes consisted in computerized analysis of sperm movement characteristics, sperm viability (EN), plasma membrane integrity (HOST and fluorescent probe) and acrosome membrane integrity using fluorescent probe. High correlation was found between EN (0.93) and HOST (0.69) in raw semen when compared with total motility after frozen-thawed semen. Low correlation was found between EN and HOST when compared with plasma and acrosomal membrane integrity in post-thawed with fluorescent probes. Since sperm motility is one of the key parameters to evaluate the quality of frozen semen, hypo-osmotic test and supra vital staining can be considered good predictive indicators in raw semen for donkey semen freezability.