Mike Phillips is preferred to Dwayne Peel at scrum half while Stephen Jones holds onto the number 10 jersey ahead of James Hook, who remains on the bench.
There are three changes in the forwards - hooker Huw Bennett and prop Adam Jones have been recalled, with Matthew Rees and Rhys Thomas making way, while Alun Wyn Jones has recovered from injury to replace his Ospreys club-mate Ian Evans in the second row.
Notably, danger man Shane Williams has scored 10 tries in his last seven Tests. The Ospreys flyer needs one try to equal Gareth Thomas' Wales record of 40 tries.
Commenting his selected team, Gatland, who coached Ireland from 1998 to 2001, said: "A number of players have had a run-out for us in the first three games of the championship and selection in most areas could be put down to the toss of a coin, which is testament to the effort the guys have put in.
"Weâ00ve had to make a judgement call at scrum half, in the front row and in the second row, but it really is a close call for us in each of those positions as well as elsewhere in the team."
The New Zealander was quick to point out that his side will travel across as underdogs despite their 100% record in the championship to date.
"Ireland are a fantastic side, theyâ00ve been a top five team in World rugby for a number of years and we have an opportunity to measure ourselves and find out where we are.
â00We'll go there as underdogs. They have lost only one game themselves in the dying minutes against France and Croke Park will be an intimidating place, but we must not be daunted by the task at hand."
The Welsh are eyeing a Triple Crown this weekend. Gatland agrees that silverware would give his players a serious boost in these closing stages of the championship, but he is wary of the quality in the Irish team, particularly play-maker Ronan O'Gara.
"You only have to look at the number of caps Ireland have throughout the side to recognise they will be a major force to be reckoned with and in Ronan O'Gara they have someone who can direct the game and really hurt opponents," he added.
â00If we donâ00t keep a tight rein on him it could be a long day for us. We will be showing Ronan and his side the utmost respect.
â00We are in a great position going for a Triple Crown. It would be nice to win it but the most important thing to us is the championship. The Triple Crown would be the icing on the cake, but at this stage we just need to make sure our performance is where we want it to be and take it from there.â0
WALES TEAM & REPLACEMENTS (v Ireland, 2008 RBS 6 Nations, Croke Park, Saturday, March 8, kick-off 1.15pm local time):
15 - Lee Byrne (Ospreys) 17 caps
14 - Mark Jones (Llanelli Scarlets) 37
13 - Tom Shanklin (Cardiff Blues) 50
12 - Gavin Henson (Ospreys) 26
11 - Shane Williams (Ospreys) 54
10 - Stephen Jones (Llanelli Scarlets) 68
9 - Mike Phillips (Ospreys) 31
1 - Gethin Jenkins (Cardiff Blues) 56
2 - Huw Bennett (Ospreys) 17
3 - Adam Jones (Ospreys) 46
4 - Ian Gough (Ospreys) 48
5 - Alun Wyn Jones (Ospreys) 19
6 - Jonathan Thomas (Ospreys) 42
7 - Martyn Williams (Cardiff Blues) 79
8 - Ryan Jones (Ospreys) 19 (capt)
16 - Matthew Rees (Ospreys) 19
17 - Duncan Jones (Llanelli Scarlets) 48
18 - Ian Evans (Ospreys) 11
19 - Gareth Delve (Gloucester) 6
20 - Dwayne Peel (Llanelli Scarlets) 61
21 - James Hook (Ospreys) 23
22 - Sonny Parker (Ospreys) 30