Line 6 (Madrid Metro)

*		Cuatro Caminos
		Nuevos Ministerios
		República Argentina
		Avenida de América
		Diego de León
		Manuel Becerra
		O'Donnell
*		Sainz de Baranda
		Conde de Casal
		Pacífico
		Méndez Álvaro
		Arganzuela-Planetario
		Legazpi
		Usera
		Plaza Elíptica
		Opañel
		Oporto
		Carpetana
		Laguna
		Lucero
		Alto de Extremadura
		Puerta del Ángel
		Príncipe Pío
		Argüelles
		Moncloa
		Ciudad Universitaria
		Metropolitano
		Guzmán el Bueno
(*) planning stage

Line 6 of the Madrid Metro opened originally between Cuatro Caminos and Pacifico in 1979. This is one of two circular lines in Madrid, but unlike Line 12, it did not open as a full circle. The circle was completed in 1995, taking four stages from its original opening.

First on 7 May 1981, the line was extended from Pacifico to Oporto, then on 1 June 1983, the line was extended from Oporto to Laguna. Thirdly the line was extended from Cuatro Caminos to Ciudad Universitaria serving Madrid's university on 13 January 1987, and lastly the line was extended from Ciudad Universitaria to Laguna on 10 May 1995, completing the circle. Arganzuela-Planetario station opened on 26 January 2007 between Legazpi and Méndez Álvaro. This station serves Madrid's Planetarium and IMAX theatre.

Line 6 is one of the busiest lines on the network, so to ease congestion on the busiest stations, Madrid adopted the "Barcelona method". This means that at some stations there are two side platforms, and an island platform. This was also used on Line S, but only two station preserves the original layout (Campamento and Carabanchel).

Line 6 uses 6-car trains of mostly class 5000, but there are a few class 7000's on this line. In the future, the second batch of class 9000 is projected to run on line 6.