To develop the biomarkers for the immune dysfunction induced by dioxin, 2, 3, 7, 8-TCDD was administered C57BL/6N mice 0.1µg TCDD/??body weight. Colony forming assay showed that the proliferation potential of hemotopoieti progenitor cells in bone marrow was reduced 35-55% more by earlier exposure. The microarray experiments were duplicated, and the candidates were restricted for the genes expressed greater than 121-fold. Resulting candidates were 55 genes. The expression patterns of the whole genes were analyzed by self-organizing maps (SOM). From these results, we selected the stage-specific genes : one genes (SOM c21 : nadh dehydrogenase subunit 5 gene) for gestational 13.5day, 13 genes (c0 : sialophorin ; spn gene, etc) for postnatal 3 week. The above genes are proposed to be a potential use of biomarker for dioxin exposure in the case of immume dysfunctions.