The 2004 European Parliament election took place on 12–13 June 2004.
The Olive Tree was the most voted list in Lombardy with 26.3%, followed by Forza Italia (25.7%) and Lega Lombarda–Lega Nord (13.8%).
| Party | votes | votes (%) | ||
|---|---|---|---|---|
| The Olive Tree | align=right valign=top | 1,432,952 | align=right valign=top | 26.3 |
| Forza Italia | 1,395,718 | 25.7 | ||
| Lega Nord | 750,842 | 13.8 | ||
| National Alliance | 391,668 | 7.2 | ||
| Communist Refoundation Party | 304,351 | 5.6 | ||
| Union of Christian and Centre Democrats | 197,662 | 3.6 | ||
| Bonino List | 149,124 | 2.8 | ||
| Federation of the Greens | 121,420 | 2.2 | ||
| Pensioners' Party | 105,965 | 2.0 | ||
| Party of Italian Communists | 101,079 | 1.9 | ||
| Italy of Values–Civil Society–Occhetto | 90,763 | 1.7 | ||
| United Socialists for Europe | 70,660 | 1.3 | ||
| LAL–LFV–UfS | 65,925 | 1.2 | ||
| Social Alternative | 54,482 | 1.0 | ||
| Others | 199,378 | 3.6 | ||
| Total | 5,423,989 | 100.0 |