Queen Sirikit Botanic Garden Herbarium (QBG), progress and contribution on species diversity for flora of Thailand Ratchada PONGSATTAYAPIPAT and Prachaya Srisanga Queen Sirikit Botanic Garden, The Botanical Garden Organization, Mae Rim, Chiang Mai, 50180, Thailand. Abstract A representative data set comprising 41,525 plant specimen records from Queen Sirikit Botanic Garden Herbarium (QBG) has been assembled. The database containing distribution data of all known vascular plant species covering all over the country have been compiled. The aim of this presentation is to demonstrate the progress on specimens collection in QBG herbarium and discuss their impact on species diversity studies for Flora of Thailand Project. Current status and prospects for the Queen Sirikit Botanic Garden herbarium are discussed. The need for targeted collecting activities is highlighted, particularly within country and the need for collaboration between major herbaria and institutes, especially in northern area, is emphasized. The QBG herbarium specimens database is available via the World Wide Web at http://www.qsbg.org/qsbgdatabase_n.htm.