Sempu Island Nature Reserve is an island conservation area that located in East Java. One of tree species that grows in the Sempu Island Nature Reserve is Maranthes corymbosa. This species is known as “triwulan” by local people. Triwulan is known as one of the plant species that has potential as building materials. Therefore, even though the conservation status of this species is still classified as safe according to the WCMC (1998) or World Conservation Monitoring Centre (i.e. LC or Least Concern), it can still experience threats because of the benefits of the wood which are known to the public. The condition of M. corymbosa itself in Sempu Island NR is still relatively well preserved because it may be due to the status of Sempu Island NR as a relatively protected conservation area. This study aims to determine the condition of the natural habitat of M. corymbosa in the Sempu Island NR and to provide additional information about several conservation efforts that have been carried out. M. corymbosa was commonly found in habitats at lowland areas, with low light intensity or shady places and in cool or humid areas in Sempu Island NR. Ex situ conservation efforts for this species have been carried out by several botanical gardens in Indonesia (Purwodadi BG, Bogor BG and Cibodas BG), one of which is by making it a collection in the garden area.