Mannose-binding lectin (MBL) is a C-type lectin produced by the liver and involved in the innate immune response. We have analyzed six SNPs of MBL2 gene--three at promoter (-550, -435, and -221), one at 5'-untranslational region (UTR) (+4), and two at coding (Gly54Asp and Leu126Leu) regions--in the Korean population (N=129), and have correlated genotypes with the serum concentration and functional characteristics. Of those, the Asp54 allele (P<10(-15)), L allele at -550 (P<10(-7)), and P allele at +4 (P=0.012) were correlated with low MBL levels. The effect of the X allele at -221 on MBL levels in the Korean population appeared to be less profound than that of other populations. The highest MBL producing promoter haplotype in the Korean population was HYP, followed by LYQ and LYP, and then LXP. From functional analysis of MBL, low MBL levels were correlated with low mannan-binding, low C4 complement activation, and lack of high ordered oligomers. Our results support that the promoter and coding polymorphisms of MBL are correlated with its functional activity as well as circulating levels, and the association patterns are quite similar to those of other populations.