Born in Barcelona, Spain, Pepita started working at the age of twelve. At the age of 14, she became involved in the Spanish Revolution and was active with the Confederación Nacional del Trabajo (CNT). In late 1937, Carpeña joined the anarchist-feminist movement Mujeres Libres, later becoming its propaganda secretary. During this time, she worked in a weapons factory. She became a women's liberationist.
