1st Mixed Brigade

1st Mixed Brigade Primera Brigada Mixta
Flag of the 11th Division of the Popular Army of the Spanish Republic of which the 1st Mixed Brigade was a part
Active	1936–1939
Country	Spain
Branch	Spanish Republican Army
Type	Mixed Brigade
Role	Home Defence
Size	Four battalions: The 1st, 2nd, 3rd and 4th
Part of	11th Division (1936 - 1939)
Garrison/HQ	Madrid
Nickname(s)	Brigada Lister
Engagements	Spanish Civil War
Commanders
Notable commanders	Enrique Líster

The First Mixed Brigade (Spanish: 1.ª Brigada Mixta), also known as Brigada Lister, was a mixed brigade of the Spanish Republican Army in the Spanish Civil War. It was disbanded on 9 February 1939.

The First Mixed Brigade was established from the Fifth Regiment on 10 October 1936 in Alcalá de Henares as a result of the reorganization of the Spanish Republican Armed forces. It was put under the command of Communist commander Enrique Lister. The first combat action of the First Mixed Brigade was the Battle of Seseña. It would suffer many losses in the Battle of Brunete, including its Cuban brigade commander Alberto Sánchez, as well as a great number of officers and Chief of Staff Major Emilio Conejo. Later the First Mixed Brigade would see action in the Aragon Offensive, the Battle of the Ebro and the Catalonia Offensive.

During the Siege of Madrid it was posted in Vallecas, where, with great losses, it helped repulse the attacks of the Army of Africa against the capital. Following this combat it was transferred to the left bank of the Manzanares River. At that time its size grew to eight battalions, being then split when the 1.ª Brigada Bis was established. The 1.ª Brigada Bis would later be renamed as the 9th Mixed Brigade.

On 19 February the First Mixed Brigade was sent to attack the Cerro de los Ángeles where the rebels had established its positions and were firing upon the surrounding area, but although it managed to gain some terrain the attack failed.