She joined the Spanish Communist Party () when it was founded in 1920. In the 1930s she became a writer for the Communist Party of Spain (PCE) publication "Mundo Obrero" and in February 1936 was elected to the Cortes Generales as a PCE deputy for Asturias. Going into exile from Spain towards the end of the Civil War in 1939, she became General Secretary of the Central Committee of the Communist Party of Spain, a position she held from 1942 to 1960. The Party then named her honorary president of the PCE, a post she held for the rest of her life. Upon her return to Spain in 1977 she was re-elected as a deputy to the Cortes for the same region she had represented from 1936 to 1939 under the Spanish Second Republic.