The European Parliament election of 2004 took place on 12–13 June 2004. The Valdostan Union was the most voted party in Aosta Valley.
| Party | votes | votes (%) | ||
|---|---|---|---|---|
| Valdostan Union–others | 21,157 | 37.6 | ||
| Forza Italia | 9,569 | 17.0 | ||
| The Olive Tree | align=right valign=top | 7,639 | align=right valign=top | 13.6 |
| National Alliance | 2,882 | 5.1 | ||
| Communist Refoundation Party | 2,398 | 4.3 | ||
| Federation of the Greens | 2,180 | 3.9 | ||
| Lega Nord | 1,661 | 3.0 | ||
| Bonino List | 1,425 | 2.5 | ||
| Union of Christian and Centre Democrats | 1,285 | 2.3 | ||
| United Socialists for Europe | 885 | 1.6 | ||
| Party of Italian Communists | 843 | 1.5 | ||
| Social Alternative | 835 | 1.5 | ||
| Italy of Values–Civil Society–Occhetto | 800 | 1.4 | ||
| Pensioners' Party | 629 | 1.1 | ||
| Consumers' List | 594 | 1.1 | ||
| Others | 1,554 | 2.8 | ||
| Total | 56,336 | 100.0 |