The cut, introduced last month in the provincial budget, was to save $90 million a year, but had been criticized by opponents and charitable groups as punishing the needy in difficult economic times.
"It's hard to admit you're wrong, but it's also important to know when to do so," Prentice told reporters in Calgary.
"Today I need to admit that we've gotten one very important thing wrong in our budget proposal.
"By reducing the charitable tax credit, we risked putting the good work of Alberta's many charitable causes at a disadvantage," he said, adding, "so today I'm going to fix that."
Prentice was surrounded by representatives of several charitable groups who broke into applause as he spoke.
The budget, tabled March 26, calls for cuts in the tax credit to 12.75 per cent from 21 per cent on charitable donations over $200.
It is one of many austerity measures in what Prentice has characterized as a game-changing document designed to help Alberta ride out the current plunge in oil prices while also preventing swings in resource prices from affecting future day-to-day spending.
The budget calls for spending cuts or freezes across government along with tax hikes, a $5-billion deficit this year and $30 billion in infrastructure debt by decade's end.
Prentice called the election earlier this month, a year ahead of the schedule according to Alberta's fixed election date law, to run on the budget, saying he needed a popular mandate to implement it.
Prentice said he doesn't contemplate further changes and said the plan to balance the budget by 2018 remains.
Opposition leaders applauded Prentice's move as the right thing to do.
But Liberal Leader David Swann said it reflects a "flip-flop" Progressive Conservative party now tailoring policy on the fly to suit election polling.
"(It's) a government that really can't be trusted to follow through on what it says it's doing," said Swann.
Recent polls suggest the Tories are in a three-way fight with the Wildrose party and the NDP in the election, which will see voters go to the polls on May 5.
Also Tuesday, Wildrose Leader Brian Jean declined to name the experts who helped craft his party's proposed budget, which promises to balance the budget by 2017 without raising taxes.
The PCs have said that would mean a $29-billion shortfall and have demanded Jean cite his sources.
Jean said he won't do that, suggesting those experts would be punished by the PCs.
"We have seen (PC government) draw no line and no distinction between bureaucrats and the government itself," said Jean.
Prentice scoffed at that.
"Speak up. There's no risk of reprisal," he said.
NDP Leader Rachel Notley, meanwhile, promised to spend $10 million a year to revive a program for student summer jobs.
Swann unveiled his party's health platform, focusing on a commitment to preventative care to reduce downstream demand for hospital beds and surgeries.
The PCs held 70 of the 87 seats in the legislature at dissolution earlier this month. The Wildrose and the Liberals each held five seats and the NDP had four. There were two vacancies and one seat was vacant.
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