Due to similarities in placentation, guinea pigs can be used as models of human cytomegalovirus infection, but they mustbe free of guinea pig cytomegalovirus. Many commercial guinea pig colonies are enzootically infected with guinea pigcytomegalovirus, which can be transmitted vertically as well as horizontally through saliva, vaginal secretions, and milk.These characteristics make its eradication in a commercial setting challenging. Because embryo transfer technology in guineapigs is in its infancy, it is not generally a viable option for obtaining animals free of guinea pig cytomegalovirus. However,a combination of hysterectomy rederivation and testing by PCR assay and serology of both dams and offspring from anenzootically infected colony produced offspring free of guinea pig cytomegalovirus.