Isaac Puente Amestoy (3 June 1896 – 1 September 1936), born in Las Carreras near Biscay, was a Basque physician and Spanish anarchist of a strong anarchist communist bent, who adhered to concerns around birth control, hygiene and sexuality. He promoted anarcho-naturism, and was active in the Confederación Nacional del Trabajo (CNT). He is best known for his pamphlet El comunismo libertario ("Libertarian Communism") published in 1932. This came to be the adopted programme of the CNT at the May 1936 Congress in Zaragoza, just prior to the Spanish Civil War.