Wales survived some anxious moments to claim their first Grand Slam since 1978 with a historic victory in Cardiff.
Mike Ruddock's side held their nerve to beat Ireland at home for the first time since 1983 and clinch the Six Nations.
A first-half try from Gethin Jenkins helped Wales to a 16-6 interval lead, with Gavin Henson weighing in with a drop goal and a long-range penalty.
Kevin Morgan's try put them 29-6 up but tries from Marcus Horan and Geordan Murphy ensured a nervous finale.
But Wales, for whom fly-half Stephen Jones added 16 points with the boot, held on to complete a remarkable transformation in fortunes.
They failed to win a match in the Six Nations two years ago, but under Ruddock they have flourished by reverting to the adventurous style of old.
Early on it seemed nerves might get the better of them, as Ronan O'Gara nudged Ireland ahead with a penalty and Jones pulled one wide in response.
But the Welsh fly-half's long diagonal punt relieved the pressure, Henson dropping a goal from the subsequent line-out to level the scores after 11 minutes.
Wales took the lead with a bizarre try in the 16th minute.
Brian O'Driscoll turned over Welsh ball but O'Gara, the Irish fly-half, dawdled for a moment too long with his clearance kick.
Tom Shanklin takes on the Irish defence
The onrushing Jenkins charged it down, the prop showing remarkable composure to kick ahead and then wait patiently before flopping on the ball over the line.
Jones' conversion put Wales 10-3 up, and Henson extended the lead with a monster 52m penalty from inside his own half before Ireland almost scored with a a great attacking move.
O'Driscoll sent Denis Hickie haring away, but Girvan Dempsey was held up on the line by another superb Stephen Jones tackle.
The visitors, by contrast, continued to shoot themselves in the foot.
A blatant Malcolm O'Kelly shove at a line-out allowed Wales relief before O'Driscoll came in the side of a ruck and Jones kicked Wales further ahead before the half-hour.
O'Gara did bring Ireland to within 10 points with a second penalty after 34 minutes, but Wales were happy with a 16-6 interval lead.
If there was a lack of authority about some of their first-half efforts, the home side dominated the opening 15 minutes on the resumption.
Jones landed two penalties to put Wales 22-6 up, with O'Gara pushing one wide at the other end.
Wales should have been further ahead, but Martyn Williams wasted a golden try-scoring opportunity when he knocked on with a huge overlap to his right.
Henson had a strong game in defence
When Ireland number eight Anthony Foley failed to finish at the right corner, forced into touch by the diminutive Shane Williams, Wales sensed their destiny.
Just before the hour, Shanklin burst through the Irish midfield and found the supporting Morgan, who dived over for a try converted by Jones.
But Wales eased off and Ireland hit back with a close-range try from replacement prop Horan.
When Murphy took advantage of David Humphreys' hanging kick to make it 32-20 with seven minutes left, a nervous finale was on the cards.
But Wales regathered themselves, and referee Chris White's final whistle sparked wild celebrations.
Wales: K Morgan; M Taylor, T Shanklin, G Henson, S Williams; S Jones, D Peel; G Jenkins, M Davies, A Jones, B Cockbain, R Sidoli, R Jones, M Williams, M Owen (capt).
Replacements: R McBryde, J Yapp, J Thomas, R Sowden-Taylor, M Phillips, C Sweeney, S Parker.
Ireland: G Murphy; G Dempsey, B O'Driscoll (capt), K Maggs, D Hickie; R O'Gara, P Stringer; R Corrigan, S Byrne, J Hayes, M O'Kelly, P O'Connell, S Easterby, J O'Connor, A Foley.
Replacements: F Sheahan, M Horan, D O'Callaghan, E Miller, G Easterby, D Humphreys, G Duffy.
Referee: Chris White (RFU).