Lichen herbaria contain a large number of parasitic fungi accidentally collected along with lichens. Various aspects of searching for lichenicolous fungi in lichen herbaria are discussed. The productivity of such searches, including the discovery of species new to science, may be higher than when these fungi are searched in nature. In one day’s work, 20–25 specimens of lichenicolous fungi can be found in the herbarium, and 2–15 specimens can be found in field studies. Keywords: lichen parasites, voucher collections.