This paper gives a survey of the native and adventitious species of the genus Medicago L. as found in the Netherlands and Belgium. The taxonomic part is preceded by an explanation of the technical terms used, and by an enumeration of the subgenera, sections and species. Four species, viz M. blancheana Boiss., M. turbinata (L.) AIL, M. praecox DC., and M. sauvagei , . „ R. Nègre appeared to be new to the Netherlands, and the following four, viz M. carstiensis Jacq., M. tornata (L.) Mill., M. turbinata (L.) All., and M. aschersoniana Urb. had not been previously recorded for Belgium. Material from the herbaria of Brussels, Leiden, Maastricht and Utrecht was used, as well as specimens from private collections of some Belgian and Dutch botanists. The taxonomic part contains a description of the genus, a key to the species and detailed descriptions of the latter, followed by notes on the general distribution, the occurrence in the Netherlands and Belgium and remarks on variability and nomenclature. The names used for some species differ from the customary ones. M. sativa L. is subdivided into three subspecies, viz subsp. sativa (M. sativa L. s.str.), subsp. falcata (M.falcata L.), and subsp. varia (M. varia Martyn). The correct name for M. obscura Retz. appeared to be M. tornata (L.) Mill.; for M. turbinata Willd. (regarding the description, not the name and synonyms) the name M. aculeata Gaertn. is used. In agreement with Urban (Ber. Deutsch. Bot. Ges. 1, 1883, p. 258) M. tuberculata Willd. is accepted as a synonym of M. turbinata (L.) All. (= M. turbinata Willd., regarding the name and the synonyms, not the description). For M. hispida Gaertn. the name M. polymorpha L. is used, thus agreeing with Shinners (Rhodora 58, 1956, p. 5). M. laciniata (L.) Mill, and M. aschersoniana Urb. are maintained as species, though the present authors believe that they are rather to be considered subspecies of the former. To give an idea of the pattern of nerves and veins and of the form of the grooves between the dorsal suture and the lateral nerves, a drawing is given, in most species, of half the lateral face of a coil. Where necessary a sketch of part of the dorsal side of a coil is added, showing also a more or less schematic transverse section of the latter.