In January 1937, following the militarization of the confederal militias, he was appointed commander of the 70th Mixed Brigade, which took part in the Battle of Jarama. Some time later he was sent to the north, where he commanded the 168th Mixed Brigade; at the head of this unit he took part in the Battle of Santander, trying to stop the nationalist advance. Later, after the fall of the northern front, he returned south to the central zone. He came to command the 25th and 22nd divisions, intervening in various military operations during the Levante Offensive.