Paul Osam's side will have learned a lot from this game against an impressive Romanian outfit. The sides were level at the break but the hosts proved too strong in the second half.
In the 17th minute Romania had a decent chance when Louis Munteanu bursts into the box and his low strike from ten yards out is turned around the post by Irish keeper Jimmy Corcoran.
Nine minutes later Irish captain Seamus Keogh fired at goal from distance but it lacked the power to beat keeper Razvan Sava.
Romania took the lead in the 29th minute when a right wing cross by Ahmed Bani found captain Radu Drăgușin and he headed home from close range.
Ireland levelled just two minutes later when a low strike across goal by Patrick Moore was spilled by the keeper and Matt Everitt pounced to turn home the loose ball.
The impressive Romanian midfielder Ahmed Bani put the hosts ahead in the 47th minute when he worked his way through the Irish defence before slotting the ball under the advancing Irish keeper Corcoran.
Romania extended their lead in the 51st minute when Corcoran was desperately unlucky to see the loose ball headed in by Munteanu after the keeper had dived full stretch to touch a powerful strike by AlexiPitu onto his crossbar.
Corcoran made another good save to deny Munteanu in the 66th minute when the striker got in a low strike from the edge of the box through a crowd of Irish defenders.
The Irish thought they had reduced the deficit in the 70th minute but Everitt's fine finish was ruled out for an infringement.
The teams will meet in a second friendly on Thursday. Osam will look for an improved display in that game but was pleased with his side's first half performance today.
"It was the first game an international level for a number of players so it was an opportunity to have a look at the new faces," said Osam.
"I felt that we did okay in the first half and some of what we worked at training came to fruition but in the second half we made a couple of errors which gave them a lift and they took control for a period of time.
"The third goal put them in pole position but then we had a perfectly legitimate goal ruled out that could have got us back into it. I've looked at it a few times and can't see where the infringement was.
"Overall we will assess this game. We've a lot of things we can look to address before the second game. It shows these players what this level is all about. They can be performing well for their clubs but when you get to international level they find that every mistake gets punished and it's all a learning curve for them."
Romania: Sava (Popa 53), Androne (Mocioacă 24), Dicu, Drăgușin, Florică (Stefanovici 77), Crivac, Grameni (Pănoiu 77), Sima (Corbeanu 53), Bani (Florescu 77), Pitu (Borcea 67), Munteanu (Țenea 67).
Republic of Ireland: Corcoran, Dunne, Kelly, Sobowale (Power 60), Agberhiere, Ebosele (Furlong 60), McKinlay (Leavy 75), Hodge, Keogh (Holt 60), Moore, Everitt (Carty 75).