This article presents data on new locations of rare and protected species of plants and fungi in the southwestern districts of the Rostov Region — Azovsky, Kuibyshevsky, Matveyevo-Kurgansky, Myasnikovsky and Neklinovsky. The study area is located in the southwestern part of the Rostov Region on the southern macroslope of the Donetsk Ridge, which passes into the North-Azov accumulative plain. These areas form a spatially compact group, located around the Taganrog Bay of the Sea of Azov from the borders of the Donetsk People’s Republic and the Lugansk People’s Republic in the north and west to the Krasnodar Territory in the south. From the east, the study area borders on the Rodiono-Nesvetaisky, Aksaysky and Kagalnitsky districts of the Rostov Region. During our research, 81 new locations of 35 species of plants and fungi (including lichens) not included in the third edition of the Red Book of the Rostov Region were identified, including 25 locations of 10 species listed in the Red Book of the Russian Federation. Based on the monitoring results, the number of fungi and plants included in the Red Book of the Rostov Region in the study area increased by 5 species, i.e. by 4.8%. Of the marsupial fungi, 3 species of lichens (Cladonia magyarica, Flavoparmelia caperata, Xanthoparmelia stenophylla) and 1 species of macromycetes (Sarcosphaera coronaria), as well as 1 species of angiosperms (Aegonychon purpurocaeruleum) were identified for the first time in this area. These finds were made in the Azov (2 species), Kuibyshevsky (2) and Myasnikovsky (1) districts. New finds of Cladonia magyarica in the Kuibyshevsky district fill the gap between the localities in the north (along the Middle Don) and the center (Donetsk Ridge) of the region, which allows us to expect other finds of the species in the southern areas of the Rostov Region. Flavoparmelia caperata was found on the trunks of Fraxinus pennsylvanica in artificial forest plantations in the Azov district. Xanthoparmelia stenophylla was found in the Kuibyshevsky district in the rocky steppe, on the outcrops of clay shale. The new find of Xanthoparmelia stenophylla in the Kuibyshevsky district complements the range of the species in the region and indicates that the species is confined to the spurs of the Donetsk Ridge in the western part of the region. The new find of Sarcosphaera coronaria in the Myasnikovsky district is the second reliable habitat of the species in the region. Both habitats are significantly distant from each other, which allows us to expect the species to be found in other areas of the region. Aegonychon purpurocaeruleum in a new location in the Azov region grows as part of a forest edge community between clearings on the territory of a hunting ground. This is a very significant find, located at a significant distance from the main range of the species in the region, complementing the line of relic exclaves of the range on the East European Plain. Thus, new finds of rare species of mushrooms and plants significantly supplement information on the nature of the distribution of rare species both in the study area and in the Rostov region as a whole. These new materials will be used in preparing the next edition of the Red Book of the Rostov Region.