The unit was created in March 1937, based on the anarchist battalions fighting in the Córdoba offensive, as well as the former Andalusia-Extremadura Column. The command of the unit was entrusted to Juan Fernández Pérez. The 88th MB became part of the 19th Division of the 8th Corps Army and was assigned to the Peñarroya-Pueblonuevo sector, where she intervened in offensive operations between March 27 and April 13. In August, the artillery commander Francisco Blanco Pedraza took over command of the unit. A few months later, in December, Blanco handed over command of the mixed brigade to militia major Francisco Rodríguez Muñoz, and the unit was incorporated into the 38th Division, with his command post in Hinojosa del Duque.