The present research was carried out to study ecto-parasites infesting rats at Mostorod and Bahteem districts, Qaliubiya Governorate, during 2008 from may till October. Three rat species parasitized by ectoparasites, R. Rattus rattus having the highest number of parasites (54.5%). This was followed by R. norvegicus (29.5%), and Mus musculus (16.0%)  Although Mus musculus did not show a high infestation rate compared to Rattus rattus or R. norvegicus, it harbored seven species of parasites. Rattus rattus and R norvegicus had six species of ectoparasites recovered. The identified ectoparasites isolated from skin and hair of rats based on their morphological characteristics were: Polyplax spinulosa (43.6%),Laelaps nuttali (23.5%), Polyplax serrata (11.3), Ornithonyssius bacoti (10.3%), Dermanyssus sanguineus (7.3%),Dermanyssus americanus (2.8)and Rhipicephalus sanguineus. (1.3).The infestation rate of the parasite varied based on the rat species, R. rattus  having the highest infestation rate. Polyplax spinulosa parasitized predominantly R. rattus, while Laelaps nuttali and Ornithonyssius bacoti ware found mainly on R. norvegicus. Dermanyssus sanguineus was predominantly R. rattus, and Mus musculus, while Dermanyssus americanus was found mainly on R. rattus. Polyplax serrata was found on R. rattus R. norvegicus, and Mus musculus while Rhipicephalus sanguineus was only recovered on Mus musculus. Ectoparasite infestation was also influenced by the sex of the host, with male rats (73.7%) manifesting a significantly higher (p<0.05) infestation rate than female rats (26.3%).         All recovered ectoparasites were common parasites of rats. Infested rats near human habitations in the area warrant possible rodent-borne diseases among the residents thus, an investigation of the occurrence of rodent-borne diseases among the dwellers may provide epidemiologic pattern related to such diseases including vectors of zoonotic diseases.