Jim Shannon, Chris Green and Mark Menzies met displaced people, clergy and political officials during their visit with the charity Aid to the Church in Need.
The group also attended the ordination of new priests in the city of Erbil.
The event was particularly poignant given that tens of thousands of Christians have been forced to leave Iraq because of Islamist extremists - including members of some of the new priests' families.
Jim Shannon, Labour MP for Strangford, said: "For me, it was an opportunity to see in some places a very thriving Church, and in other places a very persecuted Church, to meet some of those who had to flee with only the shirt on their backs as Daesh (ISIS) descended upon them to do their worst.
"There were many things that impressed me, but one thing that impressed me greatly was when we went around the camps and I met some of the displaced people was this – they had lost so much, but they had on their walls a picture of the Lord Jesus with the words: 'Jesus I will trust in thee'.
"To meet some of the families and some of the individuals who had lost loved ones to me will make a very big difference to the next time I pray."
Aid to the Church in Need provided £8.4m last year for a range of projects in Iraq.
