Results for the UK general election on 6 May 2010 Great Britain - Elections contested by Plaid Cymru
| Constituency | Candidate | Electorate | Turnout | Votes | Vote share | Vote change | Position |
| Newport West | REES, Jeff | 62,111 | 64.0% | 1,122 | 2.8% | -0.8% | 6th |
| Merthyr Tydfil and Rhymney | JONES, Glyndwr | 54,715 | 58.6% | 1,621 | 5.1% | -4.9% | 5th |
| Blaenau Gwent | DAVIES, Rhodri | 52,442 | 61.8% | 1,333 | 4.1% | +1.7% | 5th |
| Newport East | CROSS, Fiona | 54,437 | 63.3% | 724 | 2.1% | -1.7% | 5th |
| Gower | PRICE, Darren | 61,696 | 67.5% | 2,760 | 6.6% | -1.2% | 4th |
| Delyn | RYDER, Peter | 53,470 | 69.2% | 1,844 | 5.0% | -2.4% | 4th |
| Clwyd South | RYDER, Janet | 53,748 | 64.5% | 3,009 | 8.7% | -0.8% | 4th |
| Carmarthen West and South Pembrokeshire | DIXON, John | 58,108 | 69.7% | 4,232 | 10.4% | -5.1% | 4th |
| Cardiff West | ISLAM, Mohammed Sarul | 62,787 | 65.2% | 2,868 | 7.0% | -5.9% | 4th |
| Cardiff South and Penarth | ASLAM, Farida | 73,707 | 60.2% | 1,851 | 4.2% | -1.1% | 4th |
| Cardiff North | RHYS, Llywelyn | 65,553 | 72.7% | 1,588 | 3.3% | -0.9% | 4th |
| Cardiff Central | WILLIAMS, Chris | 61,165 | 59.1% | 1,246 | 3.4% | -0.1% | 4th |
| Bridgend | THOMAS, Nick | 58,700 | 65.3% | 2,269 | 5.9% | -1.0% | 4th |
| Brecon and Radnorshire | DAVIES, Janet | 53,589 | 72.5% | 989 | 2.5% | -1.1% | 4th |
| Alyn and Deeside | JONES, Maurice | 60,931 | 65.5% | 1,549 | 3.9% | +0.2% | 4th |
| Aberconwy | EDWARDS, Phil | 44,593 | 67.2% | 5,341 | 17.8% | +3.8% | 4th |
| Aberavon | NICHOLLS-JONES, Paul | 50,838 | 60.9% | 2,198 | 7.1% | -4.7% | 4th |
| Monmouth | CLARK, Jonathan | 64,538 | 72.1% | 1,273 | 2.7% | +0.6% | 4th |
| Wrexham | JONES, Arfon | 50,872 | 64.8% | 2,029 | 6.2% | +0.4% | 4th |
| Vale of Glamorgan | JOHNSON, Ian | 70,211 | 69.3% | 2,667 | 5.5% | +0.3% | 4th |
| Vale of Clwyd | WYN-JONES, Caryl | 55,781 | 63.7% | 2,068 | 5.8% | -1.4% | 4th |
| Torfaen | AB ELIS, Rhys ab | 61,183 | 61.5% | 2,005 | 5.3% | -0.9% | 4th |
| Ogmore | CLARK, Danny | 55,527 | 62.4% | 3,326 | 9.6% | -0.6% | 4th |
| Swansea West | ROBERTS, Harri | 61,334 | 58.0% | 1,437 | 4.0% | -2.5% | 4th |
| Pontypridd | BELLIN, Ioan | 58,205 | 63.0% | 2,673 | 7.3% | -3.7% | 4th |
| Preseli Pembrokeshire | JONES-DAVIES, Henry | 57,400 | 69.0% | 3,654 | 9.2% | -3.3% | 4th |
| Swansea East | JONES, Dic | 59,823 | 54.6% | 2,181 | 6.7% | -0.2% | 4th |
| Islwyn | LEWIS, Steffan | 54,866 | 63.2% | 4,518 | 13.0% | +0.6% | 3rd |
| Montgomeryshire | FYCHAN, Heledd | 48,730 | 69.4% | 2,802 | 8.3% | +1.3% | 3rd |
| Clwyd West | GRUFFYDD, Llyr Huws | 57,913 | 65.8% | 5,864 | 15.4% | +4.5% | 3rd |
| Caerphilly | WHITTLE, Lindsay | 62,122 | 62.3% | 6,460 | 16.7% | -1.4% | 3rd |
| Ynys Môn | REES, Dylan | 50,075 | 68.8% | 9,029 | 26.2% | -4.9% | 2nd |
| Rhondda | DAVIES, Geraint | 51,554 | 60.3% | 5,630 | 18.1% | +2.2% | 2nd |
| Ceredigion | JAMES, Penri | 59,882 | 63.9% | 10,815 | 28.3% | -7.6% | 2nd |
| Neath | LLEWELYN, Alun | 57,295 | 64.8% | 7,397 | 19.9% | +2.8% | 2nd |
| Cynon Valley | DAVIES, Dafydd Trystan | 50,650 | 59.0% | 6,064 | 20.3% | +6.8% | 2nd |
| Llanelli | DAVIES, Myfanwy | 55,637 | 67.3% | 11,215 | 29.9% | +3.5% | 2nd |
| Carmarthen East and Dinefwr | EDWARDS, Jonathan | 52,385 | 72.6% | 13,546 | 35.6% | -10.2% | 1st |
| Arfon | WILLIAMS, Hywel | 41,198 | 63.3% | 9,383 | 36.0% | +3.9% | 1st |
| Dwyfor Meirionnydd | LLWYD, Elfyn | 45,354 | 63.7% | 12,814 | 44.3% | -6.4% | 1st |
Turnout as calculated by the House of Commons Library, is the total number of votes cast and not spoiled, divided by the size of the electorate.
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.
This was the first election on a new set of constituency boundaries in England, Northern Ireland and Wales. The vote share calculations in those countries are based on notional results, which estimate the outcome of the previous election had it been contested on the new boundaries.