In 1936, the Basque Aguirre's government organized its own independent army, the Eusko Gudarostea, with 25,000 men.

In early December the Basques, launched an offensive in order to occupy Vitoria, the capital city of the Alava province,[1] and reduce the Nationalist pressure on Madrid.

The Republicans, led by the General Francisco Llano de la Encomienda, assembled nineteen infantry battalions, six batteries and some armoured vehicles.

[2] Opposing them, the Nationalists had one company of Requetes, two infantry battalions, one machine-gun section and an artillery battery in Villarreal.

Furthermore, Nationalist reinforces led by the Colonel Camilo Alonso Vega, reached the town.