The Member of Parliament for South Antrim, Clifford Forsythe, (Ulster Unionist) died on April 27, 2000.
A by-election to fill the seat was held on September 21. In this strongly Protestant constituency, the campaign turned on attitudes to the trouble Good Friday agreement. The election was narrowly won by the Democratic Unionist Party, fighting strongly on their refusal to co-operate with Sinn Féin in the absence of progress on arms decommissioning.
The turnout was 43%.
| Candidate | Party | Votes | Share | Change |
| William McCrea | Democratic Unionist Party | 11,601 | 38.0% | |
| David Burnside | Ulster Unionist Party | 10,779 | 35.3% | -22.2% |
| Donovan McClelland | Social Democratic and Labour Party | 3,496 | 11.4% | -4.7% |
| Martin Meehan | Sinn Féin | 2,611 | 8.5% | +3.0% |
| David Ford | Alliance Party of Northern Ireland | 2,031 | 6.6% | -5.0% |
| David Collins | Natural Law Party | 49 | 0.2% | -0.3% |
| Candidate | Party | Votes | Share |
| Clifford Forsythe | (UU) | 23,108 | 57.5% |
| Donovan McClelland | (SDLP) | 6,497 | 16.2% |
| David Ford | (APNI) | 4,668 | 11.6% |
| Hugh Smyth | (PUP) | 3,490 | 8.7% |
| Henry Cushinan | (SF) | 2,229 | 5.5% |
| Barbara Briggs | (NLP) | 203 | 0.5% |