An election to the 58th Parliament of the United Kingdom for the constituency area of Cynon Valley, held as part of the general election on 12 December 2019.
Labour hold by Beth Winter with a majority of 8,822 - 29.2% - on a turnout of 59.1%.
Candidates
| Name | Party | Vote | Vote share | Vote change |
| WINTER, Beth | Lab | 15,533 | 51.4% | -9.6% |
| CHURCH, Pauline | Con | 6,711 | 22.2% | 2.8% |
| REES-EVANS, Rebecca | BRX | 3,045 | 10.1% | - |
| BENNEY, Geraint | PC | 2,562 | 8.5% | -5.3% |
| CHAINEY, Andrew | CVP | 1,322 | 4.4% | - |
| BRAY, Steve | LD | 949 | 3.1% | 1.3% |
| MCLEAN, Ian | SDP | 114 | 0.4% | - |
Under section 13(b) of the Representation of the People Act 1985, a candidate gaining 5% or less of the vote share will forfeit their deposit.
An electorate of 51,134, having a valid vote count of 30,236 and an invalid vote count of 99.
Result declared at 02:46 on 13 December 2019.