We examined the relative contributions of three representative candidate genes for atopy (Fc ε receptor I β, IL-4, and IL-4 receptor α) to the development of atopic asthma. Four polymorphisms of the three candidate genes including Ile50Val and Gln551Arg of IL-4 receptor α, -590C/T of IL-4 promoter and Glu237Gly of Fc ε receptor I β were studied in 100 patients with atopic asthma and 100 nonatopic controls in the northern Kyushu area in Japan. Among the four polymorphisms of the three candidate genes, the Ile50 allele of the IL-4 receptor α chain gene demonstrated an association with atopic asthma subjects (p = 0.044), especially in patients with onset at 2 years of age or earlier (p = 0.034) and in patients with moderate to severe atopic asthma (p = 0.031). Gln551Arg of IL-4 receptor α, -590C/T of IL-4 promoter and Glu237Gly of Fc ε receptor I β showed no association with atopic asthma. A slight linkage disequilibrium between Ile50Val and Gln551Arg polymorphisms of the IL-4 receptor α chain gene was observed in both patients and nonatopic controls. The identification of additional atopy genes in areas with a certain genetic background is essential for genetic diagnosis and to establish new therapeutic modalities for atopic asthma.