The Constitutional Democratic Party (, PDC) was a social-liberal political party in Italy. The party emerged in 1913 from the left-wing of the dominant Liberal Union, of which it continued to be a government coalition partner. In the 1913 general election the party, which was rooted in Southern Italy while in the North it often presented joint candidates with the Liberals, won 4.8% of the vote and 40 seats in the Chamber of Deputies. In 1919 the PDC was merged with other liberal parties and groupings in the Social Democracy, that gained 10.9% and 60 seats in the 1919 general election, while other Democrats joined Liberal–Radical joint lists.

Electoral results