| Election Name: | 2004 Connecticut State Senate election |
| Country: | Connecticut |
| Type: | legislative |
| Ongoing: | no |
| Previous Election: | 2002 Connecticut State Senate election |
| Previous Year: | 2002 |
| Next Election: | 2006 Connecticut State Senate election |
| Next Year: | 2006 |
| Seats For Election: | All 36 seats in the Connecticut State Senate |
| Majority Seats: | 19 |
| Election Date: | November 2, 2004 |
| Leader1: | Donald Williams |
| Party1: | Connecticut Democratic Party |
| Leader Since1: | July 1, 2004 |
| Leaders Seat1: | 29th |
| Last Election1: | 21 |
| Seat Change1: | 3 |
| Seats After1: | 24 |
| Leader2: | Louis DeLuca |
| Leader Since2: | 2001 |
| Party2: | Connecticut Republican Party |
| Leaders Seat2: | 32nd |
| Last Election2: | 15 |
| Seat Change2: | 3 |
| Seats After2: | 12 |
| Map Size: | 300px |
| President pro tempore of the Senate | |
| Before Election: | Donald Williams |
| Before Party: | Democratic Party (United States) |
| After Election: | Donald Williams |
| After Party: | Democratic Party (United States) |
The 2004 Connecticut State Senate elections took place as part of the biennial 2004 United States Elections. All 36 seats of the Connecticut State Senate were up for re-election.[1] Senators serve two-year terms and are up for re-election every election cycle. The August 10th primary elections decided candidates that appeared on the ballot for the General election. The General Election took place on November 2, 2004.[2]
| 21 | 15 | |
| Democratic | Republican |
The Democrats kept the majority with a 21-15 Majority.