Clotario Leopoldo Blest Riffo (Spanish pronunciation: [kloˈtaɾjo βlest]; 17 November 1899 – 31 May 1990) was a Chilean social activist and labor union leader.

Later he joined Seminario Pontificio de Santiago thanks to relatives who ceded to him a scholarship aimed for the main branch of the Blest family.

After two years in Concepción Blest travelled then to the seminary of La Serena to complete his studies but by then he had decided he did not have a religious vocation so he dropped out and returned to Santiago.

[6] In 1921 when Blest returned to Santiago his mother was school director, his sister Leopoldina studied in Escuela Normalista, and his brother Fernando continued a military career.

Blest was influenced by the ideas of Recabarren whom he referred to as “the greatest and most genuine representative of the Chilean working class and of the people of Chile”.

During this time he joined the study circle called El Surco which was directed by the priest Guillermo Viviani Contreras.

The objective of El Surco was to fight for legislation that was favourable to the working class, promoting in the way the formation of labour unions.

Another organization in which Blest participated was La casa del pueblo directed by Viviani which sought to advocate syndicalism and some social Christian teachings.

The law did however not permit for the formation of trade unions so Blest decided to found a sports association in 1938 which was named Asociación Deportiva de Instituciones Públicas (ADIP).