The H19 gene is paternally imprinted both in the human and mouse (Bartolomei et al., 1991; Zhang and Tycko, 1992), although its expression pattern seems somewhat different between the two species (Jinno et al., 1995). DNA-methylation is a promising candidate for a parent-of-origin mark of the gene, and a paternal allele-specific methylation imprint was recently identified at the mouse H19 locus (Tremblay et al., 1995). We found a 50% methylated region in the human H19 gene (Jinno, unpublished data). A search for polymorphisms in this region revealed two novel AvaI and HhaI RFLPs, which contribute to the detection of allele-specific methylation at the human H19 locus.