Аннотация:To better understand the distribution and host-parasite relationships, we explored 12 large regions ofRussia and recorded new bat fleas (Insecta: Siphonaptera: Ischnopsyllidae) for Dagestan, Bashkiria, Mordovia,Khakassia and Buryatia Republics. Also we curate previously known data and registered new host-parasite associationsfor species belonging to genus Ischnopsyllus (Ischnopsyllus octactenus and I. variabilis ex Pipistrellus pygmaeus, I.intermedius ex Hypsugo savii, I. variabilis ex Myotis dasycneme, I. hexactenus ex Murina hilgendorfi) and speciesMyodopsylla trisellis. One of the associations we recorded in Altai republic is particularly interesting (Myodopsyllatrisellis – Myotis blythii). Further investigation is required to study vector role of bat fleas and the effects of fleaparasitism on their natural hosts.