Background: Monocytes, macrophages, and antigen-presenting cells (APCs) are key effectors of both innate and acquired immune responses. Such cells have been implicated in the pathogenesis of some inflammatory diseases. Differential gene expression in CD14-positive cells from patients with atopic dermatitis (AD) was studied using real-time quantitative RT-PCR to measure transcription levels of selected genes. Methods: PBMCs were prepared by Ficoll gradient separation from 30 AD patients (the anti-mite-specific IgE RAST score: 0.75 to >100 UA/ml) and 10 healthy adult individuals (the RAST score: <0.34–0.37 UA/ml) and CD14-positive cells were selected. A total of 64 genes was selected for study from groups of genes with different molecular function. Results: Genes involved in MHC class I antigen presentation, such as β2-microglobulin, subunits of an immunoproteasome and ATP-binding cassette transporter TAP2 were expressed at higher levels in the AD patients than in the healthy controls. The genes for Toll-like receptors, CD36 and IFNγ receptor were also upregulated in the AD patients. These genes are involved in MHC class I antigen presentation, recognition of bacterial pathogens and apoptotic cells. Conclusions: The upregulation of genes suggests that circulating monocytes in AD patients may be primed to differentiate into effector cells by conditions associated with AD. The upregulation of genes may prove to be a useful marker for AD.