Studied on Taxonomic Revision of Dioscoreaceae in Thailand had beenconducted by surveying and collecting specimens throughout the country, and bygathering information from herbarium specimens of Dioscoreaceae which are keptin major herbaria in Thailand and in Europe. Morphological characters wereinvestigated, described, and supported by line drawing illustrations.Morphometric studied were also elucidated for the closely related species of theGlabra group. Anatomical studied of stems, petioles and leaf blades ofrepresentative taxa were undertaken by paraffin techniques. There are 43 species of the Dioscoreaceae represented in this study,which belong to 2 genera, ~iDioscorea~i L. and ~iTrichopus~i Gaertn.. ~iDioscorea~ihas most members comprising of 42 species, while the genus ~iTrichopus~i has only onespecies. ~iDioscorea collettii~i Hook.f., ~iD. petelotii~i Prain & Burkill, ~iD.scortechinii~i Prain & Burkill, and ~iD. tentaculigera~i Prain & Burkill were the 4new records for Thailand. Material of male and female flowers and fruits whichhad never been examined, were thoroughly studied for the first time, such asthat of ~iD. craibiana~i Prain & Burkill, and ~iD. pseudo-tomentosa~i Prain & Burkill.Common species are ~iD. alata~i L., ~iD. bulbifera~i L., ~iD. glabra~i Roxb., ~iD. hispida~iDennst., and ~iD. esculenta~i (Lour.) Burkill, of which found scatteringlythroughout the country. Among these, ~iD. alata, D. esculenta~i and ~iD. hispida~i arepopularly eaten as food in Thailand. Size of the vegetative parts were foundvary greatly, depend upon the environmental conditions of their habitats, suchas soil depth, drainage and soil properties.