Bacillus Calmette-Guerin extract (BCGE) has been proven to be clinically effective for anaphylactic disease, infectious diseases and cancer. In this study, we investigated the effect of the intramuscular application of BCGE on 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD). We established an AD model in BALB/c mice by repeated local exposure of DNCB to the ear and dorsal skin. Following intramuscular application of BCGE, the ear thickness, mast cell infiltration, serum total immunoglobulin E (IgE) and histamine level were measured. In addition, levels of interleukin (IL)-4, IL-13, interferon (IFN)-γ and tumor necrosis factor (TNF)-α in the ears were assayed. BCGE reduced AD symptoms based on ear thickness, dermatitis score, histopathological analysis and serum IgE levels. In addition, BCGE inhibited mast cell infiltration into the ear and elevation of serum histamine, increased IFN-γ level and suppressed IL-4, IL-13 and TNF-α levels in the ears. Furthermore, BCGE attenuated the NF-κBp65 expression in the nuclear extract of the ear tissue. Taken together, our results demonstrated that intramuscular application of BCGE exerts beneficial effects on the symptoms of AD suggesting that BCGE may be a candidate for the treatment of AD.