Nugroho GD, Aditya, Dewi K, Suratman. 2018. Diversity of orchid (Orchidaceae) in Mount Merbabu National Park(TNGMb), Central Java. Pros Sem Nas Masy Biodiv Indon 4: 195-201. Mount Merbabu is an area managed by National Park with themanagement system into 5 resort areas, Selo, Wonolelo, Pakis, Kopeng, and Ampel. Mount Merbabu is strato-type volcano locatedgeographically at 7.5 ° LS and 110.4 ° east. Administratively, this mountain is located in Magelang regency in the western slope,Boyolali Regency on the eastern and southern slopes, and Semarang regency on the northern slope of Central Java province. Thismountain is a favorite for hikers to climb to the top of the mountain. In addition, it turns out this mountain has a great potential ofbiodiversity but not yet revealed, especially orchids. This research was conducted from 13th January 2018 to 13th February 2018 whichaims to determine the diversity of orchids in Merbabu Mountain National Park. This study used exploration method along with theobservation in tracking road within radius of 10 m to the right and left then recorded every species of orchid found. Orchids arecollected in soil or epiphytes and also observing their diversity. In this research 18 orchids such as Appendicula alba Bl., Arundinagraminifolia (D. Don) Hochr., Bulbophyllum flavescens (Bl.) Lindl., Cheirostylis sp., Coelogyne longifolia (Bl.) Lindl., Coelogyne sp.,Dendrobium sagittatum J.J.Sm., Eria multiflora (Bl.) Lindl., Habenaria tosariensis J.J.Sm., Liparis javanica J.J.Sm., Liparis pallida(Bl.) Lindl., Malaxis kobi (J.J.Sm.) J.B.Comber, Malaxis sp., Oberonia similis (Bl.) Lindl., Pholidota carnea (Bl.) Lindl., Phreatiasulcata (Bl.) Lindl., Spathoglottis plicata Bl., Taeniophyllum glandulosum Bl.