The authors report a find of Orchis simia Lamk. (Monkey-Orchid) on a hillside covered by limestone-grassland at Cadier-en-Keer in the extreme south of the Dutch province of Limburg, a few km east of Maastricht (fig. 4). The station is a south-facing hillside with calcareous deposits of Upper Senone age at varying depth in the subsoil. Up to the second world-war the area was extensively grazed by sheep; the vegetation was then open limestone-grassland. The area occupied by this vegetation is rapidly decreasing by intentional and spontaneous reafforestation. In 1972 Orchis simia was found in one of the open places left. In 1973 the same plant flowered again, producing even more flowers on a more robust stem than in the preceding year. The station in southern Limburg means an extension of the distribution area of this orchid in Belgium and northern France (VAN ROMPAEY & DELVOSALLE, 1972). Orchis simia has been found in the Netherlands only once before, viz. in the dunes on the North Sea coast at Scheveningen in 1905.