The results of lichenological research conducted for the first time in the park of the museum-estate «Ostafyevo»  «Russian Parnas» (Novomoskovsky administrative district of Moscow) are presented. The checklist of lichen biota is given. Taxonomic, ecological and sozological analyses of the investigated lichen biota have been carried out. On that basis, state assessments of lichen biota and park community has been made. 68 species from 41 genera included in 22 families of lichens and allied non-lichened fungi were found. The spectra of ecobiomorphs are complete, and the spectra of ecological-substrate groups are incomplete. Species typical for forest ecology lichen biota are noted. Nitrophytes prevail in the park of the museum-estate. 4 rare species listed in the Red Data Book of Moscow and Red Data Book of the Moscow Oblast: Cladonia macilenta, Evernia prunastri, Parmelina tiliacea, Usnea hirta, and 2 new species for the Moscow Region: Pycnora praestabilis, Ramalina europaea (the latter species is recommended for inclusion in the Moscow Red Data Book) were found. The state of lichen biota can be assessed as the best, with a low level of anthropogenic transformation, and the condition of the studied park community  as a good one. In addition, the identified lichen biota parameters indicate anthropogenic envi-ronmental changes in the park of the museum-estate compared to natural forest communities, which are caused by nitrogen pollution and dusting of the air. Keywords: lichens, biodiversity, indicator species, rare species, Red Data Book of Moscow, Red Data Book of the Moscow Oblast, estate parks, Moscow Region.