Born in Brihuega (Guadalajara), she was already a member of the Juventud Comunista (Communist Youth) and of the Partido Comunista de España (PCE) (Communist Party of Spain) during the Second Republic, before the war broke out. In April 1945 she entered Les Corts.

This was not the first time she had set foot in a Francoist prison: she had been sentenced in 1939 to 30 years, of which she served 6, spent between the prisons of Guadalajara, Durango, Santander, Ventas and Segovia. She was released in 1944 and deported to Barcelona.

She remained at Les Corts prison for nearly a year. Once out of prison she continued her underground activism and fled to France in 1961. Back in Spain she worked primarily on propaganda and prisoner support activities. From 1974 she started a long series of interviews to old fellow inmates that turned into a monumental trilogy published in the early 1980’s: Cárcel de Mujeres (Prison for Women) –two volumes- and Mujeres de la Resistencia (Women of the Resistance), an unmissable reference work for the research of the repression of women during the Franco regime.

Tomasa was awarded the Creu de Sant Jordi in 2004: an acknowledgment of her years as a fighter against the Franco dictatorship. She died in Barcelona on 25 April 2007.