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 |
| Arfon | WILLIAMS, Hywel | 41,198 | 63.3% | 9,383 | 36.0% | +3.9% | 1st |
| Aberconwy | EDWARDS, Phil | 44,593 | 67.2% | 5,341 | 17.8% | +3.8% | 4th |
| Dwyfor Meirionnydd | LLWYD, Elfyn | 45,354 | 63.7% | 12,814 | 44.3% | -6.4% | 1st |
| Montgomeryshire | FYCHAN, Heledd | 48,730 | 69.4% | 2,802 | 8.3% | +1.3% | 3rd |
| Ynys Môn | REES, Dylan | 50,075 | 68.8% | 9,029 | 26.2% | -4.9% | 2nd |
| Cynon Valley | DAVIES, Dafydd Trystan | 50,650 | 59.0% | 6,064 | 20.3% | +6.8% | 2nd |
| Aberavon | NICHOLLS-JONES, Paul | 50,838 | 60.9% | 2,198 | 7.1% | -4.7% | 4th |
| Wrexham | JONES, Arfon | 50,872 | 64.8% | 2,029 | 6.2% | +0.4% | 4th |
| Rhondda | DAVIES, Geraint | 51,554 | 60.3% | 5,630 | 18.1% | +2.2% | 2nd |
| Carmarthen East and Dinefwr | EDWARDS, Jonathan | 52,385 | 72.6% | 13,546 | 35.6% | -10.2% | 1st |
| Blaenau Gwent | DAVIES, Rhodri | 52,442 | 61.8% | 1,333 | 4.1% | +1.7% | 5th |
| Delyn | RYDER, Peter | 53,470 | 69.2% | 1,844 | 5.0% | -2.4% | 4th |
| Brecon and Radnorshire | DAVIES, Janet | 53,589 | 72.5% | 989 | 2.5% | -1.1% | 4th |
| Clwyd South | RYDER, Janet | 53,748 | 64.5% | 3,009 | 8.7% | -0.8% | 4th |
| Newport East | CROSS, Fiona | 54,437 | 63.3% | 724 | 2.1% | -1.7% | 5th |
| Merthyr Tydfil and Rhymney | JONES, Glyndwr | 54,715 | 58.6% | 1,621 | 5.1% | -4.9% | 5th |
| Islwyn | LEWIS, Steffan | 54,866 | 63.2% | 4,518 | 13.0% | +0.6% | 3rd |
| Ogmore | CLARK, Danny | 55,527 | 62.4% | 3,326 | 9.6% | -0.6% | 4th |
| Llanelli | DAVIES, Myfanwy | 55,637 | 67.3% | 11,215 | 29.9% | +3.5% | 2nd |
| Vale of Clwyd | WYN-JONES, Caryl | 55,781 | 63.7% | 2,068 | 5.8% | -1.4% | 4th |
| Neath | LLEWELYN, Alun | 57,295 | 64.8% | 7,397 | 19.9% | +2.8% | 2nd |
| Preseli Pembrokeshire | JONES-DAVIES, Henry | 57,400 | 69.0% | 3,654 | 9.2% | -3.3% | 4th |
| Clwyd West | GRUFFYDD, Llyr Huws | 57,913 | 65.8% | 5,864 | 15.4% | +4.5% | 3rd |
| Carmarthen West and South Pembrokeshire | DIXON, John | 58,108 | 69.7% | 4,232 | 10.4% | -5.1% | 4th |
| Pontypridd | BELLIN, Ioan | 58,205 | 63.0% | 2,673 | 7.3% | -3.7% | 4th |
| Bridgend | THOMAS, Nick | 58,700 | 65.3% | 2,269 | 5.9% | -1.0% | 4th |
| Swansea East | JONES, Dic | 59,823 | 54.6% | 2,181 | 6.7% | -0.2% | 4th |
| Ceredigion | JAMES, Penri | 59,882 | 63.9% | 10,815 | 28.3% | -7.6% | 2nd |
| Alyn and Deeside | JONES, Maurice | 60,931 | 65.5% | 1,549 | 3.9% | +0.2% | 4th |
| Cardiff Central | WILLIAMS, Chris | 61,165 | 59.1% | 1,246 | 3.4% | -0.1% | 4th |
| Torfaen | AB ELIS, Rhys ab | 61,183 | 61.5% | 2,005 | 5.3% | -0.9% | 4th |
| Swansea West | ROBERTS, Harri | 61,334 | 58.0% | 1,437 | 4.0% | -2.5% | 4th |
| Gower | PRICE, Darren | 61,696 | 67.5% | 2,760 | 6.6% | -1.2% | 4th |
| Newport West | REES, Jeff | 62,111 | 64.0% | 1,122 | 2.8% | -0.8% | 6th |
| Caerphilly | WHITTLE, Lindsay | 62,122 | 62.3% | 6,460 | 16.7% | -1.4% | 3rd |
| Cardiff West | ISLAM, Mohammed Sarul | 62,787 | 65.2% | 2,868 | 7.0% | -5.9% | 4th |
| Monmouth | CLARK, Jonathan | 64,538 | 72.1% | 1,273 | 2.7% | +0.6% | 4th |
| Cardiff North | RHYS, Llywelyn | 65,553 | 72.7% | 1,588 | 3.3% | -0.9% | 4th |
| Vale of Glamorgan | JOHNSON, Ian | 70,211 | 69.3% | 2,667 | 5.5% | +0.3% | 4th |
| Cardiff South and Penarth | ASLAM, Farida | 73,707 | 60.2% | 1,851 | 4.2% | -1.1% | 4th |
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.