The Social Democratic Party of Switzerland (also rendered as Socialist Party of Switzerland; German: Sozialdemokratische Partei der Schweiz (SP); French: Parti socialiste suisse (PS); Italian: Partito Socialista Svizzero; Romansh: Partida Socialdemocrata de la Svizra) is a social-democratic party in Switzerland.
In 2003, it held 52 mandates (out of 200) in the Swiss National Council (first chamber of the Swiss parliament); 9 (out of 46) in the second chamber and 2 out of 7 mandates in the Swiss Federal Council (executive body). By 2005, it held 23,8% of the seats in the Swiss Cantonal governments and 23,2% in the Swiss Cantonal parliaments (index "BADAC", weighted with the population and number of seats). At the last legislativeelections, 22 October 2007, the party won 19,5 % of the popular vote and 43 out of 200 seats. [1]