Data on natural HEV infection of infection in monkeys are limited. We report a case of hepatitis E virus genotype 4 infection in captive non-human primates (cynomolgus monkeys) imported from Vietnam. Phylogenetic analysis demonstrated that HEV infection was not the result of spillover from single source of infection, but rather the persistent circulation of HEV-4 among cynomolgus monkeys or multiple infections by related strains from a human or swine reservoir.