The National Red List of Flora 2020 is the most updated and comprehensive source of information on available species, threatened plants and health of biodiversity in this country. It was last updated and published in 2012. Since then many development programmes, climatic changes as well as new investigations into the plant wealth of this country have occurred. Thus updating this list is keenly felt. The National Herbarium of the Department of National Botanic Gardens (DNBG) played a key technical role in publication of National Red data Book together with the Biodiversity Secretariat (BDS). The National herbarium preserves and maintains scientifically treated specimen collections of all native plants in Sri Lanka. All specimens and information available in the herbarium were used with tremendous effort of scientists attached to the National herbarium in preparation of the plant lists, mapping data and compilation of the book. Moreover, inputs on species distributions and verifications on conservation status were given by a group of experts from various sectors.