After more than fifty years of Gunnar Seidenfaden's researches on the orchids of Indochina, published in 1992, several researches on Lao orchids have been undertaken by local and international institutions contributing to extend the Lao orchids data and knowledge. This presentation focuses on the terrestrial orchid taxa, which have been updated from the results of these research projects, available botanical literature and related publications. Nearly two hundred terrestrial orchids have been listed, the most represented genera being Habenaria Willd., Paphiopedilum Pfitzer, Liparis Rich., Calanthe R.Br. and Phaius Lour. while Anthogonium Wall. ex Lindl., Chrysoglossum Blume, Myrmechis (Lindl.) Blume and Thaia Seidenf. are the least represented. Among the terrestrial orchid identified/listed, many genera do appear as new records with very few species, like Acanthephippium Blume ex Edndl. (2 species), Didymoplexiopsis Seidenf. (2), Hetaeria Blume (2), Chrysoglossum Blume (1), Collabium Blume (1), Gastrodia R.Br.(1), Lecanorchis Blume (1), Thaia (1), Didymoplexis Griff. (1), Didymoplexiella Garay (1), etc.... Unfortunately many of the genera and species have not been found again, the appropriate time and physical conditions being important parameters to take into account for collecting and studying terrestrial orchids.