Hepatitis G virus was successfully transmitted to macaqucs.Five animals were inoculatcd with scrum from a paticnt whose serum was HGV RNA positive by RT PCR.The serum and bioptic liver tissues were examined by RT PCR,ELISA and light microscope respectively.The results showed that 2 macaques with normal ALT levels had seroconversion of HGV RNA and anti HGV IgG for over 50 weeks and their liver tissues had the changes of acute and chronic hepatitis which were very similar to those of patients with hepatitis G.The HGV positive serum was subpassaged in another macaque at the 7th week after transmission.The changes was as same as that of the first passage animals.