The present study was aimed to the exposure rams epididymal sperms sourced from abattoir to two doses of Zinc oxide and Cerium Oxide Nanoparticles on sperms viability after stored at 4C0 for 72 hrs. The experiment was carried out in the artificial insemination lab at the University of Mosul, College of Veterinary Medicine, Mosul, Iraq. Sixteen healthy mature Awassi rams, aged between 1-4 years, were slaughtered at slaughterhouse, total of sixteen pairs of testicles (n=32) were collected. Five parts of sperm samples were separated and diluted in egg yolk extender, the first one left as control, second part received Cerium oxide NPs at 50 μg/ml, third part received Cerium oxide NPs at 25 μg/ml, while Zinc oxide NPs as 1 mg/ml was add to the fourth part and 1.5 mg/ml of Zinc oxide NPs added to fifth part. All sperms samples stored at 4C0 for 72hrs. Sperms live percentage, individual motility, sperms abnormalities were estimated. Data of present study showed that cerium oxide NPs at 50 μg/ml had best effect on sperms viability and improve sperms live percentages, individual motility, low sperms abnormalities were reported after storage. Cerium oxide NPs at 25 μg/ml had mild improve of sperms viability. Zinc oxide NPs at dose 1 mg/ml and 1.5 mg/ml had no effect or falling sperms viability after 24, 27 hrs of storage. In conclusion, CeO2 NPs in dose 50 μg/ml improve epididymal sperm characteristics after storage at 4C0 for 72hrs. Zinc oxide NPs had not improve sperms viability.