EU deal 'fails Wales' says First Minister Carwyn Jones
The first minister says the EU budget cut could be "deeply unfair" to the poorest parts of west Wales and the valleys.
EU leaders agreed a 908bn euros (£768bn) budget limit for 2014 to 2020, about 3% lower than the current seven-year period.
Carwyn Jones said early estimates show Wales could lose £400m in funding.
But Prime Minister David Cameron said it would be "good for the UK and good for Europe".
Responding to the deal, the First Minister Carwyn Jones warns that the agreement "fails to deliver" for Wales.
He said this would result in significant cuts to funding programmes.
"We are disappointed that the agreement fails to deliver the level of investment in jobs and growth needed in Wales," said Mr Jones.
Analysis by Tomos Livingstone, political correspondent
It is difficult to imagine a more different response from Carwyn Jones to that of David Cameron.
Mr Jones says it will not do anything to stimulate the economy and create growth and jobs in Wales or indeed across Europe.
He says he is very disappointed that west Wales and the valleys, which are areas that have received a large amount of European funding over the years, appear to be missing out as a result of the budget cuts.
Mr Jones says they are missing out to pass money over to areas in Britain and across Europe that are already well off.
Over the past few weeks, the Welsh government has been going through all the European projects in Wales with a fine toothcomb looking at which ones are working and which ones are not.
I suspect that process will now intensify because we have got this confirmation that there is going to be a good deal less money to spend in those areas.
It is a cut of around £400m for west Wales and the valleys, we expect - under some estimates, they were expecting a rise of £400m.
So very disappointing from Carwyn Jones's perspective but, as with so much in politics, it depends which way you look at things.
"We are especially concerned that the most vulnerable part of Wales - west Wales and the Valleys - appears to be losing out to wealthier regions in the UK. This cannot be seen as a fair reflection of priorities for Wales.
"Despite all of our efforts to promote a fair deal to protect Wales' interests, the agreement reached by the European Council is deeply unfair to the poorest parts of the EU.
"The prime minister says this is a 'good deal for Britain'. He will need to explain how it's a good deal for Wales."'Siphoned away'
Speaking after the marathon negotiations in Brussels, David Cameron said he could look the taxpayer in the eye and argue that he had helped deliver the agreement.
"I think the British public can be proud that we have cut the seven-year credit card limit for the EU the first time ever," he said.
The deal would see a fall in the share of money given to agriculture, while protecting areas such as research and development, he said, adding that "working with allies it is possible to take real steps towards reform in the European Union".
But the Welsh first minister said the agreement had come at a high price for Wales.
End Quote Dr Elizabeth Haywood South East Wales Economic Forum
We should be looking at some regionally significant programmes rather than having lots of little dissipated mini programmes all over the area”
"The Welsh government has always recognised the need for discipline in the overall EU budget but it cannot be right for EU money allocated to the UK to be siphoned away from poorer regions, like west Wales and the Valleys - to richer regions elsewhere," he said.
"We must now look to the UK government to make a fair allocation to Wales of its much reduced structural funds budget, so that we can continue our work in transforming the economy of our country."
Dr Elizabeth Haywood, director of the South East Wales Economic Forum, told BBC Radio Wales it looked like west Wales and the valleys would get £400m less, but it was possible to make improvements in how the funds received were spent.
"I argued when I was chairing the city regions task group... we should be looking at some regionally-significant programmes rather than having lots of little dissipated mini-programmes all over the area," she said.
"If we could actually achieve that this time round, we could end up getting more value out of our European funds.
"I think it's also got to be remembered that whatever you put in, in terms of European funding, has to be match-funded from somewhere else and of course that's been getting more difficult as the economy has been in a more difficult state."
Dr Haywood added there was the possibility Wales would not have been able to spend the amount it received because match funding could not be found.