Agios Kosmas (Greek: Άγιος Κοσμάς, also Κοσμάς ο Αιτωλός - Kosmas o Aitolos) is a village, a community and a municipal unit of the Grevena municipality. Before the 2011 local government reform it was an independent municipality. The seat of the municipality was in Megaro. The 2011 census recorded 49 residents in the village, 75 residents in the community and 870 residents in the municipal unit. The community of Agios Kosmas covers an area of 9.496 km2 while the municipal unit covers an area of 115.087 km2. The village is named after the 18th-century saint Cosmas the Aetolian.