The member of Gesneriaceae (African violet) are widely propagated for indoor ornamental plants. However, in vitro propagation of native species of Thai Gesneriaceae has not been reported elsewhere. Therefore, the objective of this study is to optimize sterilization methods for in vitro of Thai Gesneriaceae along with the other species of African violet by vary difference concentration of Clorox and time variation. As the result, we found that there are not appropriate methods. This preliminary data will be applied for studying the appropriate sterilization using antibiotic to reduce the contamination.