A contribution on lichen diversity in the “Mariazellerland” and selected localities in the area Naßköhr-Hinteralm (Northern Alps, Styria). – The lichen flora in the central part of the region “Mariazellerland” and of selected localities in the area Naßköhr-Hinteralm in northern Styria has been investigated. Both areas belong to a system of minor limestone mountain ranges and massifs named “Steirisch-niederösterreichische Kalkalpen”. The first investigation area, the “Mariazellerland”, has always been used intensively by forestry. A total of 213 taxa of lichens (178 of them epiphytes) have been found, 36 of them are endangered in the Alps. In the second investigation area, “Naßköhr-Hinteralm”, only 8 localities could be studied in detail, two relatively natural forest fragments and some old, free-standing phorophytes. In spite of these few sampling localities, a total of 26 endangered epiphytic lichen species has been recorded. Remarkable sampling localities of both investigation areas are described, including comments on selected lichen species. In addition to the material from the two main areas of investigation, numerous collections from neighbouring areas have been dealt with, including 23 lichen species endangered in the Alps. In addition, the results of a lichenological collecting trip to the forest reserve “Rotwald” are briefly discussed. Biatora chrysantha is recorded from the province of Styria for the first time.