| Election Name: | 2008 United States Senate election in Iowa |
| Country: | Iowa |
| Flag Image: | Flag of Iowa (xrmap collection).svg |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 2002 United States Senate election in Iowa |
| Previous Year: | 2002 |
| Next Election: | 2014 United States Senate election in Iowa |
| Next Year: | 2014 |
| Election Date: | November 4, 2008 |
| Image1: | Tom Harkin official portrait (cropped).jpg |
| Nominee1: | Tom Harkin |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 941,665 |
| Percentage1: | 62.66% |
| Nominee2: | Christopher Reed |
| Party2: | Republican Party (United States) |
| Popular Vote2: | 560,006 |
| Percentage2: | 37.26% |
| Map Size: | 240px |
| U.S. Senator | |
| Before Election: | Tom Harkin |
| Before Party: | Democratic Party (United States) |
| After Election: | Tom Harkin |
| After Party: | Democratic Party (United States) |
The 2008 United States Senate election in Iowa was held on November 4, 2008. Incumbent Senator Tom Harkin sought re-election to a fifth term in office. Unlike Harkin's three previous reelection bids, he was not challenged by a sitting United States Congressman but instead faced small businessman Christopher Reed, who won the Republican primary by just a few hundred votes. Harkin defeated Reed in a landslide, winning 94 of Iowa's 99 counties., this is the last time that a Democrat has won a U.S. Senate election in Iowa.
| Source | Ranking | As of | ||
|---|---|---|---|---|
| align=left | The Cook Political Report[1] | October 23, 2008 | ||
| align=left | CQ Politics[2] | October 31, 2008 | ||
| align=left | Rothenberg Political Report[3] | November 2, 2008 | ||
| align=left | Real Clear Politics[4] | November 4, 2008 |
| Poll source | Dates administered | Christopher Reed (R) | Tom Harkin (D) | |||
|---|---|---|---|---|---|---|
| align=left | Survey USA[5] | April 21–23, 2008 | 20% | 59% | ||
| align=left | Research 2000[6] | June 10, 2008 | 37% | 53% | ||
| align=left | Rasmussen Reports[7] | July 10, 2008 | 37% | 55% | ||
| align=left | Rasmussen Reports[8] | August 7, 2008 | 36% | 60% | ||
| align=left | Rasmussen Reports[9] | September 17–18, 2008 | 37% | 60% | ||
| align=left | Survey USA[10] | October 23, 2008 | 41% | 57% | ||
| align=left | Rasmussen Reports[11] | October 29, 2008 | 35% | 61% |