The genus Psychotria L. (Rubicaeae) is probably the world's largest predominately woody genus (Davis et al., 2001), with perhaps around 2,000 species (Sohmer, 1998). It has a pantropical distribution and often found in tropical forest. Recently, 42 species and 11 species were recorded in Thailand and Lao PDR, respectively. Two species are newly recorded including P. tonkinensis Pit. which is newly recorded for Thailand and Lao PDR and P. calocarpa Kurz is a new record for Thailand. Seven species are found both in Thailand and Lao PDR viz. P. adenophylla Wall., P. asiatica L., P. prainii H. Lév., P. pseudoixora Pit., P. sarmentosa Blume, P. serpens L. and P. tonkinensis. Eighteen species, namely P. aganosmifolia Craib, P. ardisioides Craib, P. brunescens Craib, P. chartacea Craib, P. elipsoidea Craib, P. fuscenscens Craib, P. induta Craib, P. kerii Govaerts, P. krossii Craib, P. kratensis Craib, P. lineolata Craib, P. lutescens Craib, P. plana Craib, P. rutila Craib, P. sempervirens Geddes, P. smithiae Geddes, P. thailandensis Ruhsam and P. winitii Craib, are regarded as endemic to Thailand, while P. thorelii Pit. is considered endemic in Lao PDR.