She was the first Minister of Social Work in Cuba.
Mederos founded several organizations including the School of Social Services at the University of Havana; the Foundation for Social Services, which developed programs for children's organizations in Cuba; "Of Human Rights" (New York City, 1961); and a Cuban exile lobby that worked for the release of political prisoners.
A suffragist, Mederos was a co-founder of the Alianza Nacional Feminista, a suffragist organization active in Cuba during the 1920s.
She was the founding vice president of the National Association of Cuban American Women (NACAW).
Mederos is "considered the most prominent Cuban woman of the 20th century".