The aim of this study is to investigate whether three mononucleotide polymorphisms at the locus -1082,-819 and -592 in the promoter region of the IL-10 gene are associated with chronic severe hepatitis. The IL-10-592 and IL-10-1082 polymorphisms were genotyped by polymerase chain reactionrestriction fragment length polymorphism analysis (PCR-RFLP) while polymerase chain reaction-sequence specific primer (PCR-SSP) assay was used to test the IL-10-819 polymorphism. The polymorphisms of IL-10-1082, -819 and -592 genes were detected in 98 patients with chronic severe hepatitis (CSH), 478 patients with chronic hepatitis B (CHB), 223 asymptomatic (chronic) HBV carriers (ASC) and 267 patients with self-restricted HBV. There was significant difference of the polymorphisms of IL-10-1082, IL-10-819 and IL-10-592 genes between CSH group and other groups. The frequency of AA genotype at IL-10 gene promoter -1082 locus in chronic severe hepatitis patients was higher than that in asymptoatic HBV carriers (x2 = 13. 314, P = 0.001), and self-restricted HBV patients (x2 = 13.545, P = 0.000) ; the frequency of CC and AC genotype at IL-10 gene promoter -592 locus in chronic severe hepatitis patients was higher than that in chronic hepatitis patients(x2 =15.970, P=0.000)(x2 =20.414, P=0.000), asymptomatic HBV carriers (x2 =21.283, P=0.000) (x2 =28.309, P =0.000) and self-restricted HBV patients(x2 = 17.047, P =0.000) (x2= 16.528, P =0.1300); the frequency of TC genotype at IL-10 gene promoter-819 locus in chronic severe hepatitis patients was higher than that in chronic hepatitis patients(x2 = 58.961, P = 0. 000),asymptomatic HBV carriers (x2 = 53. 255, P = 0. 001 ) and self-restricted HBV patients (x2 =39.616, P = 0.001). So interleukine-10 gene polymorphism was associated with the chronic severe hepatitis.