Tory leader William Hague said the chancellor was giving with one hand, but taking back with the other through "stealth taxes".
He announced targeted tax cuts for business, less well off families, savers and pensioners.
Mr Brown said the Budget was about "investing in the long term" and ensuring "stability".
But Mr Hague said: "Every measure he has announced is set against the stealth taxes."
He added: "He gives back to people for a limited period only a tiny part of what the chancellor has taken from them."
Mr Hague compared Mr Brown to "the thief who steals your car and comes back the next day to return the hub caps."
'Labour MPs duped'
He told Labour MPs that they had been duped into believing Mr Brown's Budget.
"For example, when he talks about helping women and children they will remember that he scrapped the married couples allowance."
He continued: "People will be suspicious about some of the claims he has made today.
"So many of the claims he makes on budget day turn out to be false."
'People conned'
Mr Hague suggested voters knew the tax cuts were not real.
"As the chancellor tries to con people that he has been suddenly been converted to tax decreases he must think the people of this country are stupid."
The Tory leader said stealth taxes had hit the poorest fifth of households the hardest.
Mr Hague said the chancellor could have use his Budget to reform Whitehall, tackle welfare fraud and give money back to "the hardworking people of this country".
He also suggested Mr Brown would have been better to take more pensioners out of the tax net and that he could have done more to help married couples.
'Double counting'
Liberal Democrat leader Charles Kennedy said the chancellor had behaved as Labour's election campaign chairman in his Budget.
He also hit out at the failure of the chancellor to scrap university tuition fees in England and Wales.
Mr Kennedy also accused Mr Brown of "double counting" over the extra money for schools and hospitals.
"All of next year's extra spending is simply money he failed to spend this year."
He added: "The choice is now clear. Only the Liberal Democrats will invest significantly in more police, teachers, nurses and raise the pension substantially.
"And we will tell people how much they will pay in tax and what their money is being spent on - so there will be no stealth taxes with the Liberal Democrats."
The Scottish Nationalist Party and Plaid Cymru have also been critical.
SNP leader John Swinney said the Budget did little to combat stealth taxes.
Plaid Cymru leader Ieuan Wyn Jones said the measures would do nothing to help farmers or manufacturing.