To better understand the distribution and host-parasite relationships, we explored 12 large regions of Russia 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 associations for 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 species Myodopsylla trisellis. One of the associations we recorded in Altai republic is particularly interesting (Myodopsylla trisellis – Myotis blythii). Further investigation is required to study vector role of bat fleas and the effects of flea parasitism on their natural hosts.