The paper reports the results of lichenological investigations in Asveja Regional Park (eastern Lithuania). A large part of the study was performed during the joint 18th Symposium of Baltic Mycologists and Lichenologists (BMLS) and Nordic Lichen Society meeting (NLF), September 19–23, 2011. A list of 259 species is presented, 30 of them are new to Lithuania. Arthonia helvola, Bacidina sulphurella, Candelariella lutella, Catillaria croatica, Cladonia conista, Gyalecta derivata, Lecanora quercicola, Leptosphaeria ramalinae, Strigula jamesii, Trichonectria rubefaciens, Verrucaria banatica, V. boblensis, V. christiansenii, V. illinoisensis, V. inornata, V. nigrofusca, V. trabicola, Zwackhiomyces diederichii are recorded for the first time in the Baltic countries. New lichens for Lithuania are: Bacidia incompta, Caloplaca crenulatella, C. pyracea, Catinaria atropurpurea, Lecanora populicola, L. semipallida, Mycobilimbia epixanthoides, Ramalina dilacerata, Verrucaria inaspecta, and new lichenicolous fungi are: Cladosporium licheniphilum, Stigmidium microspilum, Xenonectriella leptalea. Eighteen species included in the Lithuanian Red Data Book were recorded which is the highest number known for any studied area in Lithuania.