Atopy, which is characterized by increased levels of immunoglobulin E (IgE) against common environmental allergens, is considered the strongest predisposing factor for asthma and atopic dermatitis (AD). Mutations in the gene encoding serine protease inhibitor Kazal-type 5 (SPINK5) are responsible for Netherton syndrome, a rare skin disorder characterized by greatly elevated IgE levels with atopic manifestations. A recent study of Caucasian AD families showed that maternally derived alleles of the SPINK5 gene are associated with development of AD and asthma, suggesting the parent-of-origin effect for the development of atopic diseases in the SPINK5 gene. We studied the possible association of the SPINK5 gene for the development of atopic diseases by determining the genotypes of five polymorphisms in a Japanese population. Ttransmission disequilibrium tests revealed an association of SPINK5 polymorphisms with AD but not with asthma. Our data indicate that the SPINK5 gene is associated with AD across ethnicities.