The election was called by President Ciampi, after he dissolved the houses of Parliament on 8 March 2001.

[3] The legislature ended after its natural course of five years, soon after the houses were dissolved again by Ciampi on 11 February 2006.

[4] The election leading to the composition of this legislature was characterized by the use of decoy lists ("liste civetta") by both major coalitions (the House of Freedoms and the Olive Tree), in order to "de facto" turn the scorporo (partially compensatory) system implemented by the electoral law into a parallel voting system.

At the beginning of the legislature there were nine life senators (Giovanni Leone, Francesco Cossiga and Oscar Luigi Scalfaro as former Presidents, and the nominated life senators Carlo Bo, Norberto Bobbio, Gianni Agnelli, Giulio Andreotti, Francesco De Martino and Paolo Emilio Taviani).

After the death of Leone, Bo, Bobbio, Agnelli, De Martino and Taviani, and the nomination of the new life senators Rita Levi-Montalcini, Emilio Colombo, Mario Luzi (who died in February 2005), Giorgio Napolitano and Sergio Pininfarina, the total number of senators at the end of the legislature was of 320.