The aim of this experiment was to study the optimal age of Stemona curtisii plantlets for acclimatization. The in vitro shoots of S. curtisii were cultured on Murashige and Skoog solid medium supplemented with 1 mg L-1 naphthalene acetic acid to induce roots. Then, the plantlets from in vitro culture of 4, 8 and 12 week-old were transferred into the soil and their survival rate during the acclimatization process in the greenhouse was investigated. It was found that the 8 week-old plantlets had the highest survival rate of 80%. However, to enhance the survival rate of these plantlets, a soilless culture technique as a possible approach for the acclimatization was considered. Eight week-old plantlets were transferred into either, soil, a hydroponic system (nutrient film technique), coconut fiber or sand. The plantlets which were cultivated in coconut fiber or hydroponic culture showed 100% survival rate with the highest average number of new roots per plant. However, the mean root length of the plantlets grown in hydroponic system was significantly higher than that grown in coconut fiber.