One of the plants endemic of West Kalimantan is Rafflesia Tuan-mudae. R. Tuan-mudaefound at the Raya Pasi Nature Reserves in West Kalimantan, especially at Mount Poteng. Information about the habitat of R. Tuan-mudae at Mount Poteng is still not found. The purpose of this study was to get information about characteristics of habitatR. Tuan-mudae at Gunung Poteng Raya Pasi Nature Reserve. Data collection was carried out in May 2018,R. Tuan-mudae habitat analysis was carried out using a survey method. Data retrieval using observer plots was determined by purposive sampling technique. Using a double observation plot measuring 20 x 50 m, totaling 4 plots. The results of the study found 145 R. Tuan-mudae individuals, at an altitude between 431-503 masl, slope 18.25%, temperature 25 ° C-26.1 ° C with humidity between 83% -89%. This Rafflesia lives in the host plant Tetrastigma sp.Keywords: characteristics, habitat, Rafflesia Tuan-mudae
