OBJECTIVE:To explore the NS gene structure and mutation of Chinese strains of human Parvovirus B19 (HPV B19). METHODS: NS genes of R19-XA17, XA18 and XA20 strains from three Chinese children with acute aplastic anemia were amplified by PCR, and then the amplified products were sequenced directly. RESULTS: Compared with the sequence of Au strain, four bases of NS genes of B19-XA17, XA18 and XA20 strains changed and their coding amino acids changed also. CONCLUSIONS: Genetic diversity exists in mucleotide sequences of NS gene of HPV B19 isolated from the serum of Chinese children. [Chin J Contemp Pediatr, 2003, 5(1): 5 - 7]