The present article represents the first part of a review of fossil heterostigmatic mites collected from late Eocene Rovno amber. Here, mites of the families Tarsocheylidae, Dolichocybidae, and Acarophenacidae are described, with Tarsocheylidae and Dolichocybidae recorded for the first time from amber. A new genus and four new species are described, namely, Hoplocheylus similissp. nov. (Tarsocheylidae), Dolichocybe elongatasp. nov. (Dolichocybidae), Proadactylidium fossibilisgen. and sp. nov. and Paradactylidium sineunguissp. nov. (Acarophenacidae). The extant species Acarophenax lacunatusCross and Krantz, 1964 and A. assanoviLivshitz and Mitrofanov, 1974 are transferred to the new genus Proadactylidium. A revised key to the genera of Acarophenacidae is presented. The homologies of prodorsal setae in Acarophenacidae are reconsidered and reviewed.