Peter Robinson said lessons had to be learned
The DUP must learn from its worst ever European election result, party leader Peter Robinson has said.
Diane Dodds was beaten into third place behind Jim Nicholson from the Conservatives and Unionists. Sinn Féin's Bairbre de Brun topped the poll.
The DUP had previously topped the poll in every European election since 1979.
First Minister Mr Robinson is expected to reshuffle his executive team within the next week. He said the party could learn lessons from Sinn Fein.
"The reason it (the election results) has happened is that very high profile people within the party have been in government," he said.
"I'm not one who regularly blogs but I did read one comment which I thought was pertinent where it said Sinn Fein have an awful lot to learn from the DUP in terms of governance but the DUP have an awful lot to learn from Sinn Fein in terms of communicating with their base.
"There's a lot of truth in that."
DUP candidate Diane Dodds took the third of Northern Ireland's three MEP seats at the third stage on Monday without reaching the quota.
Diane Dodds is now an MEP without reaching the quota
The DUP had 32% of the entire first preference vote in 2004, this time it fell to 18.2%.
Former DUP MEP Jim Allister, now the leader of Traditional Unionist Voice, polled more than 66,000 votes, but was later eliminated.
On Monday, Mr Robinson told the BBC that there was "nothing more certain to make people stay at home" than unionist bickering and division.
"We had a three way split for the unionist vote and the consequences can be seen," he said.
"I am disappointed. I believe that a very significant section of our support base stayed at home. There's a message in that for us. We have to connect and communicate with those people. We have to win those votes out.
"It's our responsibility to ensure we can motivate people to come out to the polls and that's what we'll set about doing. You'll see a very different DUP after this election."
He said a series of factors had contributed to the depletion in DUP votes.
"We have to face up to the fact that while a large portion of the unionist electorate find it very difficult to have Sinn Fein in government, I think that we did the right thing," he said.
"I believe that we have undersold our case. People need to know there was no more acceptable alternative available. I don't believe we have communicated that message sufficiently to our own support base."
BBC Northern Ireland Political Editor Mark Devenport said the DUP would need to have a post-mortem examination on the results.
"They will have to try to work out to what extent this was simply an anti-power-sharing vote, reflecting Jim Allister's views, given that this was the first election since the DUP did its deal with Sinn Fein," he said.
"And to what extent it is more... the Westminster expenses saga, concerns about double jobbing, concerns about the candidate, Diane Dodds, that have fed into people maybe making a protest vote at the European elections, which they know will send a shot across the bows of the DUP, but won't bring Stormont down."
According to official figures, 488,891 people in Northern Ireland voted. That translates to a turnout of just below 43% - a big drop in the last election.