Old World macaque Nonhuman primate (NHP) species are the most commonly used primate species for biomedical research. Macaca mulatta (rhesus macaque) and Macaca fascicularis (cynomolgus macaque) are species of Asian macaques that are commonly used for viral and/or immunological studies (Influenza Virus and SARS CoV2). This research aim was to assess the potential use of M. fascicularis for the pre-clinical study of viral infection in humans. M. fascicularis were intranasally and/or intratracheally inoculated with HPAI H5N1 Virus and SARS-CoV-2 in different time studies and then tested with rt-PCR to test the infection over time. Infection with HPAI H5N1 virus and SARS-CoV-2 was found in mucosal swab samples. No clinical signs were found in all subjects for both virus infections. With several emerging viral infections becoming pandemic, M. fascicularis has proved to be a very beneficial animal model for investigating human viral infections and would be useful for showing the pathophysiology and developing therapeutic agents and vaccines.<br />