Human metapneumovirus (hMPV) is a newly discovered virus, it belongs to the family of Paramyxoviridae, subfamily of Pneumovirinae, Genus Metapneumovirus. Among 18 viruses detected among Severe Acute Respiratory Infection (SARI) patients and hospitalized in the province of Hai Duong from 2009 to 2011, hMPV ranked a rather high with 5.0 percent, just after the new pandemic influenza HI N 1, rhinovirus, and seasonal influenza virus B. In this study of longitudinal surveillance, molecular techniques were applied to identify some genetic characteristics of hMPV among SARI patients hospitalized in Hai Duong during 2009-2011. The phylogenetic analysis of G and F genes revealed the same clustering of linage A2b and sub-genotype B1, and B2, of which B2 and A2b were predominant. There was a shift from B2 in 2009 and 2010 to A2b in 2011. These sequences have the most homology with those isolated at the same period in Asian countries. Nevertheless, the diversity of G gene was very high. The association between the genotype and disease severity was not mentioned in this study. The study has shown that during 3 consecutive years of follow-up in Hai Duong, from 2009 to 2011, the genetic characteristics of hMPV was consistent with those of Asian countries.