This paper analyses the decline of Italy's centre-left in the last 30 years. It does so by tracing the peculiar evolution of Italian social democracy. Contrarily to other Western European countries, Italy was characterized by a Communist party that was electorally stronger than the Socialist one. Through the 1990s, the Italian Communist Party evolved and changed its name twice. Then, in 2007, it merged with other progressive parties (included a Christian-democratic one) to create the Democratic Party (PD), which exists until today. The paper reviews several potential explanations for the decline of Italian social democracy, like the decline of the working class, structural changes in the economic system, and the party’s stances on the welfare state and immigration. It also shows how the PD is nowadays, like other social-democratic parties in Europe, the party of high-education voters, who have a high trust in political institutions and in the EU – certainly not the party of the ‘left behind’ citizens.