The Socialist Party of Chile was co-founded on 19 April 1933, by Colonel Marmaduque Grove, who had already led several governments, Oscar Schnake, Carlos Alberto Martínez, future President Salvador Allende, and other personalities.

These ideas took hold in the labour movement at the beginning of the 20th century and, along with them, the various communist, anarchist, socialist, and mutualist ideals of the time were diffused by writers and leaders such as Luis Emilio Recabarren.

The PS integrated into the new leftist coalition following Cerda's death, now named Democratic Alliance, which supported the candidacy of the Radical Juan Antonio Ríos, who was triumphantly elected.

Oscar Schnake occupied once again the post of Promotion and the socialist Pedro Populate Vera and Eduardo Escudero Forrastal assumed the positions of Lands and Colonization and Social Assistance, respectively.

In the IX Congress of the PS of the year 1943 Salvador Allende displaced Marmaduque Grove as Secretary General and withdrew his party from the government of Ríos.

In the XI Ordinary Congress the current "revolution" of Raúl Ampuero was imposed and he assigned to academic Eugenio González the making of the Program of the Socialist Party which defined its north; the Democratic Republic of Workers.

[13] Bernardo Ibáñez, Oscar Schnake, Juan Bautista Rosseti and other anticommunist socialists supported it with enthusiasm; while the board of directors of the party directed by Raúl Ampuero and Eugenio González rejected it.

[14] The Socialist Popular Party proclamation, in its XIV Congress, carried out in Chillán in May 1952, as its presidential standard bearer to Carlos Ibáñez del Campo, despite the refusal of the senators Salvador Allende and Tomás Chadwick.

In spite of the loss, the unification of the socialist parties had a new leader, and Chile was one of the few countries of the world in which a Marxist had clear possibilities to win the presidency of the Republic through democratic elections.

The overwhelming triumph of Eduardo Frei Montalva over the candidate of the FRAP Salvador Allende Gossens in the presidential elections of September 1964 caused demoralization among the followers of the "Chilean way to socialism".

In July from 1967 the senators Raúl Ampuero and Tomás Chadwick and the representatives Ramón Silva Ulloa, Eduardo Osorio Pardo and Oscar Naranjo Arias were expelled, and founded the popular socialist union (USOPO).

In the XXII Congress, which took place in Chillán in November 1967, the political became more radical, under the influence of Carlos Altamirano Orrego and the leader of the Ranquil Rural Confederation, Rolando Calderón Aránguiz.

Salvador Allende Gossens was proclaimed as the party's presidential candidate, with 13 votes in favor and 14 abstentions, among them that of its secretary general, Aniceto Rodriguez, of Carlos Altamirano Orrego, and of Clodomiro Almeyda Medina.

The position of the PS on joining the government of the UP became more radical when senator Carlos Altamirano Orrego took over as party leader, having been elected at the XXIII Congress in La Serena in January 1971.

Meanwhile, from the United States, a concerted plan was underway to prevent socialists from gaining power around the world, including CIA backing for the right wing in Chile.

President Salvador Allende refused to relinquish power to the Armed Forces, and ultimately committed suicide in his office at the Palace of La Moneda, during an intensive air bombardment of the historic edifice.

Having reviewed the consequences of the defeat of the Unidad Popular, and observed the experiences of refugees of "true socialism" in Eastern Europe, and seeing the lack of a cohesive strategy to continue against Pinochet's regime, there was deep dissent within its exterior organization, whose central management was in the German Democratic Republic.

In April 1979, the Tercer Pleno Exterior, the majority sector of the party, named Clodomiro Almeyda as the new Secretary General, Galo Gómez as the Assistant Secretary and expelled Carlos Altamirano, Jorge Arrate, Jaime Suaréz, Luis Meneses and Erich Schnake from the party, charging them with being "remnants of a past which is in the process of being overcome who testify to the survival of a nucleus which is irreducible and resistant to the superior qualitative development of a true revolutionary vanguard".

They convened the Fourth National Protest Day (11 August 1983) and proposed, in September 1983, the formation of the Socialist Bloc, the first attempt at a unification of Chilean socialism under the slogan "Democracy Now!".

[citation needed] In September 1986, the politico-military method of "mass violent insurrectionist uprisings" was finally aborted after the failure of "Operation 20th century", as the assassination attempt on Pinochet by the FPMR was called.

After the elections the XXV Congress was convoked at Costa Azul, which took the momentous decision for Chilean socialism to abandon its traditional isolationism and join the Socialist International.

Finally the PS-Arrate (or "renewal" PS) dropped its candidate Ricardo Lagos and added itself to the candidacy of Aylwin, who as president of the Christian Democratic Party was one of the main opponents of the Popular Unity government.

Between 22 and 25 November 1990 the "Salvador Allende Unity Congress" was held, with past leaders such as Raúl Ampuero and Aniceto Rodriguez and the Christian Left headed by its president Luis Maira and its two representatives (Sergio Aguiló and Jaime Naranjo) joining the party.

Finally, the Socialist Party decided to have itself recorded under its own name and symbols in the electoral rolls, and gave a two-year time limit to its members to opt for the PS or the PPD.

A significant number of "renewal socialists" did not return to the PS; among them Erich Schnake, Sergio Bitar, Guido Girardi, Jorge Molina, Vicente Sotta, Víctor Barrueto and Octavio Jara.

In power, the socialists Enrique Correa (as the minister General Secretary of Government), Carlos Ominami (Economy), Germán Correa (Transportation), Ricardo Lagos and Jorge Arrate (Education) and Luis Alvarado (National Resources) entered the cabinets of President Aylwin, while in the House of Representatives, the socialists José Antonio Viera-Gallo and Jaime Estevéz exercised its presidency.

The left (PS-PPD) backed Ricardo Lagos as the Concertación candidate for the 1993 presidential elections, but he was defeated by the Christian Democrat Eduardo Frei Ruiz-Tagle, gaining only 36.6% of the vote in the primary on 23 May.

After Frei became president, the Socialists took up senior posts in his first cabinet: Interior (Germán Correa), Planining (Luis Maira), Labor (Jorge Arrate), and Public Works (Ricardo Lagos).

Socialist ministers in his first cabinet were José Miguel Insulza (Interior), Ricardo Solari (Labor), Carlos Cruz (Public Works), and Michelle Bachelet (Health).

In the 2009 parliamentary elections, the PS led by Escalona suffered a serious defeat: it lost its dominance of the Senate, holding just 5 seats, and its deputies reduced in number form 15 to 11.