Atopic dermatitis is a chronic recurrent inflammatory skin disease. Colonization and infections by various microorganisms are frequent due to dysfunction of skin barrier and impaired immune response. Demodex folliculorum plays an important role in the pathogenesis of rosacea, acne vulgaris, perioral dermatitis, seborrheic dermatitis and blepharitis, particularly in immunocompromised indivudials. A 12- month-old girl who has the diagnosis of atopic dermatitis since three months of age was admitted to our outpatient clinic. Laboratory analysis revealed a serum total IgE and egg-spesific IgE levels of 998 IU/L and 4.46 IU/mL, respectively. Besides dietary restriction, topical medications were administered with the diagnosis of atopic dermatitis and food allergy. The specimens, obtained by the technique of superficial skin biopsy from pustular lesions of the patient who had ongoing symptoms despite elimination diet, revealed D. folliculorum. Isolation of an ectoparasite, D. folliculorum, on pustular lesions of a patient with atopic dermatitis denotes that ectoparasites which can also be found in normal flora may present as a pathogen. Demodex infestation should be considered in patients with atopic dermatitis who have treatment-resistant lesions.