Jim Nicholson, the UUP's Euro MP, has called on his party supporters to remember the benefits of EU membership as they call for a referendum on the issue.
He said the province had received nearly £6.25bn in aid from Europe in the past 25 years.
"Since 1988 Northern Ireland has received over €7,533m (£6,227m at today's rates) of funding and my question is: if we were not in the EU, where else would this money come from?" Mr Nicholson told delegates in the party's annual report.
In a speech to delegates he added: "There are also downsides to EU membership relating to its increased and increasing powers without accountability. The level of red tape and the cost that that can impose, and there is a need for meaningful reform."
He went on: "We are clear in the Ulster Unionist Party on the issue of EU membership. We believe in the three Rs which he listed as:
* a review – to assess the nature of the UK's relationship with the EU
* a renegotiation – to improve the terms of the UK's membership
* And a referendum – the public must be given a say on EU membership.
Mr Nicholson has been a Euro MP since 1989, by far the longest serving in the province, and he stressed this experience in his speech.
"I have worked to build up strong working relationships right across the Parliament, with Commissioners and with Commission and Council officials. I know how Brussels operates and I have worked in a range of policy areas to gain access and open doors for local businesses, organisations, officials and ministers," he said.
Mr Nicholson claimed credit for bringing Dacian Ciolos, the EU Agriculture commissioner to Northern Ireland to discuss CAP reform.
He attacked comments by Anna Lo, the Alliance Euro candidate, that she personally favoured Irish unity in the long term.
He accused Alliance of doing "so much back peddling" on her comments that "you'd be forgiven for thinking the Giro D'italia had arrived early!"