Climate changes observed in the last years pose a serious threat to biodiversity. Similar climatic changes, nevertheless, have occurred many times in our planet's history. Relict plants that survived after experiencing climate change can give us information about the past and the future of species. The rich biodiversity in the countries of Southern Europe, including Bulgaria, is shaped by a large number of relict plants. To date, the biodiversity of relict plants in Bulgaria has not been systematically described and remains somewhat unknown. Our aim is to systematize available information and present biodiversity of relict vascular plants in Bulgaria. Using a critical approach, we discovered 346 species of 207 genera and 81 families of relict origin. This number accounts for 8.74% of the natural flora of Bulgaria and 8.43% of the total flora of Bulgaria (which includes foreign species). We divided relict plants into two groups: tertiary relicts (183 species) and quaternary relicts (163 species). The quaternary relicts we divided into 3 groups: glacial relicts (143 species), interglacial relicts (13 species) and postglacial relicts (7 species). Among the relicts with the largest number are perennial herbaceous plants, followed by shrubs and trees. 144 relict species have conservation status.