The problem of biodiversity conservation and rational use of natural resources has become a priority concern of humankind. The intensification of the negative impact on biosphere leads to changes in floral composition of natural habitats and to biodiversity loss. Currently, the conservation of plant diversity of a territory is based on monographic studies of separate taxonomic groups.  As a result of field investigations, examination of herbaria and study of scientific literature regarding the subfamily Cichorioideae Kitam. (family Asteraceae Dumort.) in the wild flora of the Republic of Moldova, a list of rare species, which includes 30 taxa, was made and their category of endangerment was determined. The present research was carried out on 10 rare species of Cichorioideae, which as a result of the assessment and categorization according to the criteria of the International Union for the Conservation of Nature (2001, 2003) [2,3] were classified as threatened species and were assigned to the following categories: Critically endangered [CR] Endangered [EN] and Vulnerable [VU].  1. Crepis capillaris (L.) Wallr. - EN [B2ab(iii,iv,v); C2a(i); D]. It is a xeromesophilous species, which grows in meadows, scrubs and steppe slopes from the central and southern parts of the investigated region. The identified populations are poor, represented by few specimens. 2. Hieracium laevigatum Willd. - CR [B2ab(iii,v); D]. Mesophilous species, which grows in meadows and at the edge of the forests, it has been found in only one place in the zone of forests from our country. This taxon has been proposed for inclusion in the Red Book of the Republic of Moldova, 3rd edition. 3. H. vagum Jord. - VU [B2ab(iii,v); D2]. Mesophilous species, characteristic of ecosystems with oak and ash trees, it was found in two localities in the center of the region. This species is endangered by the presence of towns, villages and transport networks near the areas where it grows, and also by deforestation. 4. Pilosella caespitosa (Dumort.) P.D.Sell et C.West. - VU [B2ab(iii,iv,v); C2a(i)]. Mesophilous species, which grows at the edge of forests, in glades and scrubs. In the local flora, there are known seven locations where it can be found. Populations are threatened by deforestation and unregulated tourism. 5. Scorzonera austriaca Willd. – CR [B2b(iii,iv); C2b]. This species is protected by law in the Republic of Moldova [4], proposed for inclusion in the Red Book of the Republic of Moldova, 3rd edition, included in the Red Book of Ukraine [5].  6. Scorzonera mollis Bieb. - VU [B2ab(iii,iv,v); C2a(i)]. It is protected by law in the Republic of Moldova [4],  proposed for inclusion in the Red Book of the Republic of Moldova, 3rd edition, included in the Red Book of Vascular Plants of Romania [1]. It is a species with highly fragmented habitat, threatened by the reduction of the steppe areas and their use for agricultural purposes. 7. Scorzonera purpurea L. - VU [A4ac; B2b(iii,iv,v)]. Taxon is protected by law in the Republic of Moldova [4]. It is a xeromesophilous species, threatened by the drastic reduction of the areas where it grows; it is in satisfactory condition only in inaccessible, impassable or protected areas.  8. Scorzonera stricta Hornem. - EN [B2ab(iii,iv)]. It is protected by law in the Republic of Moldova [4]. It is found only in the southern part of the country. It forms small populations, with a small number of individuals. 9. Scorzonera taurica Bieb. – EN [B2ab(iii,iv); C2a(i)]. It is a xeromesophilous species, characteristic of steppe sectors. The reduction of the specific habitats leads to the decrease of the viability of populations, and sometimes – to their disappearance.  10. Trommsdorfia maculata (L.) Bernh. - VU [A4ace; B2ab(iii,iv,v); C2a(i)]. It is a mesophilous species. In the last decade the number of areas where the species grows has declined considerably.