The Italian regional elections of 3–4 April 2005 were a major victory (11-2) for the centre-left The Union coalition, led by Romano Prodi.

The centre-right coalition, governing in the national government, was defeated in all the regions it held, except for its strongholds in Lombardy and Veneto, whose population is anyway a fourth of Italian population.

The elections resulted in the national government, led by Silvio Berlusconi, to acknowledge defeat and open a crisis, which resulted in the formation of Berlusconi III Cabinet, with some ministers being substituted.

Due to a series of bureaucratic issues involving the presentation of the list of Social Alternative in Basilicata, the election there would have been held two weeks later.

The fact that the centre-left was particularly strong in small regions led to the even result of the 2006 general election.