The article contains information about a special-purpose working collection of carotenogenic microalgae from the Department of Animal Physiology and Biochemistry of the Federal Research Center of the Institute of Biology of the Southern Seas named after A.O. Kovalevsky. Collection was established within the framework of scientific and applied research of the Institute to study the mechanisms of stress tolerance in euribiontic and extremophillic single cell phototrophs and to identify commercially relevant sources of highly valuable ketokarotinoids of astaxanthin group used for medicine and food production. The collection includes 44 microalgal strains of various taxonomic and ecological specializations with a pronounced ability to hyperaccumulation of secondary carotenoids and lipids under extreme conditions (drying, nutrient starvation, high-intensity illumination, extreme temperature, salinities, toxicants, etc.). The main sources of accessions of the collections are direct exchange of carotenogenic species with leading Russian and foreign collections of microalgae and own field collections in the Black Sea areas of the Crimea and Caucasus. The majority of strains in the collection are representatives of two orders of Chlorophyceae class - Chlamydomonadales (25 strains) and Sphaeropleales (15 strains), as the phenomenon of secondary carotenogenesis is widespread in these orders. The majority of these strains are inhabitants of ephemeral fresh-water reservoirs, aerophilic and soil microalgae. All strains are maintained under controlled conditions on agarized mineral media as unialgal cultures. Descriptions the collection accessions include the following information: a) the current taxonomic status of the species, verified by the updated data from the corresponding collections and algological databases of Algaebase and NCBI Taxonomy Browser; b) the bionymes and known synonyms of the species; c) the time and source of the strain deposition, d) the author, geographic location and biotope from which the strain was isolated; e) the accession number of sequences associated with the strain in NCBI (if any); f) the nutrient medium on which the strain is maintained in the IBSS collection. The significance of the collection for morphological and physiological and biochemical studies of growth, secondary carotenegenesis, and biotechnological potential in green microalgae is discussed.