Fifty-eight individuals belonging to 10 species of bats, insectivores, and pikas were examined for helminths from 4 collection sites in Mongolia in 1999. Two species of bats (Vespertilio murinus and Eptesicus gobiensis) were infected with a single species of trematode (Plagiorchis vespertilionis), which represents a new record for the country. One individual of E. gobiensis also harbored 1 unidentified filaroid nematode. The acanthocephalan Moniliformis moniliformis was found in the hedgehog Hemiechinus auritus. Cestodes in the genus Catenotaenia and the herein described Schizorchis mongoliensis n. sp. were recovered from pikas belonging to the species Ochotona alpina. Schizorchis mongoliensis n. sp. is distinguished from other members of the genus by shorter strobila length accompanied by earlier maturation of proglottids, as well as a distinct vaginal valve and secondary lateral seminal receptacle.