Objective of research: To study the role of phoresy of the louse Mallophaga on the population of the louse-fly Hippoboscidae. Material and methods: In 1997–2015 more than 10000 birds were caught; from them about 2000 louse-flies Hippoboscidae were collected and studied. Results and discussion: 12 cases of phoresy of the louse Mallophaga on the louse-fly Hippoboscidae were recorded: 7 cases of phoresy of Columbicola columbae on pigeon louse flies Pseudolynchia canariensis collected from pigeons (Columba livia); one case — phoresy of the louse Ricinus rubeculae on the louse fly Orniyhomyia fringillina from the robin (Erithacus rubecula); one case — phoresy of the louse on the louse fly O. avicularia from the rook (Corvus frugilegus); one — phoresy of the louse on louse fly O. avicularia from the cuckoo (Cuculus canorus); one — phoresy of the louse on the louse fly Ornithoica turdi from the nightingale (Luscinia luscinia); one case — phoresy of the louse on the louse fly O. chloropus from Luscinia svecica.