ABSTRACT
House dust mites were collected from 8 different areas in Great Cairo. Nine species of mites were recovered from indoors. In order of abundance, they were Dermatophagoides pteronyssinus, D. farinae, Tyrophagous putrescentiae, Acarus siro, Cheyletus malaccensis, Blomia kulagini, Acheles graciles, Ornithonyssus bacoti and Lepidoglyphus destructor. All these mites were collected mainly from Bulaq El- Dakrour [28.8%] and El-Wayly [27.6%]. The least number [1.8%] of species [only 3] was collected from Madent El-Salam. Pet and stray dogs and cats, domestic birds and commensal rodents were more or less reported in the majority of the examined areas. Also, patients with history of allergy of unknown cause were reported in 10 out of 80 houses examined [12.5%]. The role played by house dust mites in causing allergic manifestations was important environmental disease agents