Demodex is a common ectoparasite of human skin. The association with blepharitis is mentioned in various researches. Sixty-two-year-old patient with left eyelid swelling and erythema for 11 months which did not respond to antihistaminic treatment was referred to our laboratory. Demodex folliculorum was detected on standard superficial skin biopsy smear prepared from around the eye and on the eyelash epilated from his left eyelid. The patient responded dramatically to topical treatment (metronidazole 1% + urea 2%) and was cured. The detection of D. folliculorum in this blepharitis case shows the pathogenic potential of this ectoparasite which can also be found in normal skin flora. Demodex infestation should be considered in cases of blepharitis which do not respond to therapy. Methods for investigating Demodex spp. should be added to blepharitis diagnosis algorithm for accurate diagnosis and appropriate treatment.