| Election Name: | 1988 Illinois's 21st congressional district special election |
| After Election: | Jerry Costello |
| Before Election: | Melvin Price |
| Representative | |
| Percentage2: | 48.53% |
| Popular Vote2: | 31,257 |
| Party2: | Republican Party (United States) |
| Nominee2: | Robert Gaffner |
| Percentage1: | 51.46% |
| Country: | Illinois |
| Popular Vote1: | 33,144 |
| Party1: | Democratic Party (United States) |
| Nominee1: | Jerry Costello |
| Election Date: | August 9, 1988 |
| Next Year: | 1988 |
| Next Election: | United States House of Representatives election in Illinois, 1988 |
| Previous Year: | 1986 |
| Previous Election: | United States House of Representatives election in Illinois, 1986 |
| Ongoing: | no |
| Type: | presidential |
| Before Party: | Democratic Party (United States) |
| After Party: | Democratic Party (United States) |
A special election to the United States House of Representatives for Illinois's 21st congressional district was held August 9, 1988.
The winning candidate would serve briefly in the United States House of Representatives to represent Illinois in the 100th Congress until the General election on November 8, 1988.
On April 22, 1988, Incumbent U.S. Representative Melvin Price died of cancer after 22 terms.[1] A special election was held to fill the vacancy caused by his death.