Adam33 is a member of a family of genes that encode membrane-anchored proteins with a disintegrin and a metalloprotease domain and that are primarily expressed in lung fibroblasts and bronchial smooth muscle. The human Adam33 gene is located on chromosome 20p13, a region that has been linked to asthma and bronchial hyperresponsiveness. Recently, the polymorphisms in Adam33 have been found to be associated with asthma. In this study, we performed polymorphism scanning of the entire genomic region, including the promoter region of Adam33, by direct sequencing. We identified 16 novel polymorphisms in the Adam33 gene. Among these novel polymorphisms, three polymorphisms (-2154G-->A, -753T-->A, and -330C-->T) were found to be in the promoter region and one polymorphism (13491 G-->A) was located in 3' untranslated region of the Adam33 gene.