Canine atopic dermatitis (AD) is a complex genetically-linked immunological hypersensitivity which has similar clinical signs and pathological features to human AD, and involves immune dysregulation and skin barrier impairment. Accumulating evidence supports the involvement of specific microRNA (miRNA) in regulating the immune system, and in autoimmune and other immune-dysfunction diseases. Few studies to date report the role of miRNA in human AD and asthma and no information is available for canine AD. Considering the homology between dog and human miRNA sequences, canine AD may serve as a useful animal model to study the role of miRNA in human AD. To explore the immune-regulatory mechanisms in canine AD, expression patterns of miRNA from leukocytes of atopic dogs (n=7) were compared to controls (n=6), utilising the Affymetrix GeneChip miRNA 2.0 array, which contains probes from 133 species, including 291 Canis familiaris miRNAs probes (cfa-miR). Fifteen differentially expressed cfa-miRs were identified; some with previous links to immune dysfunction diseases in humans. The cfa-miR-31 was present at lower levels in atopic dogs, suggesting a potential dysregulation that may relate to T-regulatory cells. Further analysis, utilising the comparative aspect of the array will be presented. This study suggests that miRNAs may be altered in atopic dogs, may provide biomarkers to assist with diagnosis, and are potential therapeutic targets for AD.