Kaempferia siamensis Sirirugsa (Zingiberaceae) is found in only a few natural habitats in Northeastern Thailand and it is commonly used as an ornamental plant and vegetable. It is rare species endemic to Thailand and therefore, needs conservation measures. In vitro propagation of K. siamensis by a tissue culture technique was investigated as a tool for its ex situ conservation. Buds from shoots of K. siamensis (0.5 cm in length) were cultured on Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurine (BAP) combinations with a-naphthaleneacetic acid (NAA) and 6-Furfurylaminopurine (Kinetin) combinations with NAA for eight weeks. The best number of axillary shoot induction and root numbers were 7.1 and 24.2, respectively when the axillary buds were cultured on MS medium supplemented with 2.0 mg l^-1 BAP and 0.1 mg l^-1 NAA. The highest response of the microrhizome was 70.0% when shoot buds of K. siamensis were cultured on MS medium supplemented with 2.0 mg l^-1 BAP, 1.0 mg l^-1 NAA, 1.9 mg l^-1 AgNO₃, and 70.0 g l^-1 sucrose after 20 weeks. Rooted shoots were transplanted into soil, sand and soil mixed with sand (1 : 1, v : v) under greenhouse conditions and their survival was 100%. RAPD fingerprinting revealed 84.6% genetic similarity between randomly selected micropropagated plants and field-grown donor plants.