Cornwall and the Isles of Scilly are set to get about £500m in the next round of Objective One funding.
Problems agreeing the EU budget meant there had been fears over whether Cornwall would get further aid.
However following the deal at the weekend, Objective One is secure for another term, from 2007-2013.
The exact amount has still to be agreed but the minister for the regions, Alun Michael, said it is likely to be a third greater than the current £350m.
The news has been welcomed by two of Cornwall's Liberal Democrat MPs.
Chairman of the Parliamentary Team for Cornwall, Andrew George MP said: "Up until today's announcement the Government has been hell bent on denying Cornwall what it deserves, which is a continuation of European regional aid.
"The biggest prize of all is that Europe has forced the Government to recognise Cornwall as a unique region in economic terms.
"I hope the Government will not make us go cap in hand to their Departments and regional quangos to plead for every ha'peth worth of matched funding."
'Great news'
North Cornwall MP Dan Rogerson said: "We still don't know exactly how much Cornwall will get from 2007 and we will monitor developments very closely as further announcements are expected next year.
"This gives Cornwall another 8 years to undertake serious forward planning and more major regeneration projects."
Carleen Kelemen, Director of the Objective One Partnership, said: "This is great news for Cornwall and the Isles of Scilly.
"With this next round of investment the people of Cornwall and the Isles of Scilly have the opportunity to build on this success and continue the journey towards a long term prosperous future."
Andrew Mitchell, Cornwall County Council Economy Portfolio Holder, said: "Confirmation of this new programme means that we can get on with the work we need to do for Cornwall.
"The successes of the Objective One Programme together with the strategy being developed by the Cornwall Economic Forum give us the direction to continue our journey to greater prosperity."