Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants with various toxic effects including immune suppression. However, the molecular mechanism of their toxicity has not been fully clarified. The purpose of this study was to identify novel aryl hydrocarbon receptor (AhR)-regulated genes involved in PAH-induced immunotoxicity using a highly-sensitive DNA chip, 3D-Gene(TM) Human Immunity & Metabolic Syndrome 9k. Leucine-rich repeat-containing protein 25, glucosaminyl (N-acetyl) transferase 3 (GCNT3), thyroxine-binding globulin, aldehyde dehydrogenase 8A1, diacylglycerol O-acyltransferase homolog 2 (DGAT2), haptoglobin, neuron navigator 2 isoform 1, hemopexin and bile acid receptor were found to be up- or down-regulated by PAHs via AhR. Among these genes, GCTN3 and DGAT2 were responsible for immune responses. Therefore, disruption of the expression of these genes via AhR may be one of the causes of the immunotoxicity of PAHs.