The party was founded on 19 July 1974 during the Carnation Revolution. In its first democratic elections in 1975, the CDS-PP won 16 seats out of 230 – increasing to 42 in the 1976 legislative election. The party entered a short-lived coalition with the Socialist Party (PS) before joining the Democratic Alliance (AD). The party has been involved in centre-right coalitions with the Social Democratic Party (PSD) from 1980 to 1983 and again from 2002 to 2005. In the 2009 legislative election, the party won 21 seats, its most since the 1985 election, and increased it to 24 in 2011, leading to it forming a coalition government with the PSD.