Flanker McCarthy is the surprise inclusion in the squad while Luke Fitzgerald and Rory Best are named after recovering from injuries picked up for Ireland in the autumn internationals.
Rookie Rhys Ruddock, son for former Wales coach and current Ireland under 20 coach Mike, is named in the squad after making his debut on the 2010 summer tour to Australia but there is no room for Munster scrum-half Tomás O'Leary.
Coach Kidney said: "As always the selection of the squad is never an easy one but certainly the level of competition in each position is probably as great as it has ever been over the last two years.
"Players have been really pushing their performances for their provinces, so that level of competition can only be good.
"That translates into more competition for each place in the squad and then for the first selection against Italy, which can only be a good thing coming into the championship."
Ireland squad for the RBS 6 Nations opener against Italy on February 5:
Backs: Tommy Bowe (Ospreys), Gordon D'Arcy (Leinster), Gavin Duffy (Connacht), Keith Earls (Munster), Luke Fitzgerald (Leinster), Shane Horgan (Leinster), Ronan O'Gara (Munster), Brian O'Driscoll (Leinster), Eoin Reddan (Leinster), Jonathan Sexton (Leinster), Peter Stringer (Munster), Andrew Trimble (Ulster), Paddy Wallace (Ulster).
Forwards: Rory Best (Ulster), Tom Court (Ulster), Sean Cronin (Connacht), Leo Cullen (Leinster), Stephen Ferris (Ulster), Jerry Flannery (Munster), John Hayes (Munster), Cian Healy (Leinster), Jamie Heaslip (Leinster), Shane Jennings (Leinster), Denis Leamy (Munster), Mike McCarthy (Connacht), Donncha O'Callaghan (Munster), Paul O'Connell (Munster), Sean O'Brien (Leinster), Mick O'Driscoll (Munster), Michael Ross (Leinster), Rhys Ruddock (Leinster), David Wallace (Munster).
Ireland Wolfhounds squad:
Backs: Isaac Boss (Leinster), Ian Humphreys (Ulster), Denis Hurley (Munster), Keith Matthews (Connacht), Fergus McFadden(Leinster), Johne Murphy (Munster), Niall O'Connor (Ulster)
Tomas O'Leary (Munster), Eoin O'Malley (Leinster), A.N. Other.
Forwards: Nigel Brady (Ulster), Tony Buckley (Munster), Willie Faloon (Ulster), Jamie Hagan (Connacht), Chris Henry (Ulster), Kevin McLaughlin (Leinster), Dominic Ryan (Leinster), Donnacha Ryan (Munster), Devin Toner (Leinster), Dan Tuohy (Ulster), Damien Varley (Munster), Brett Wilkinson (Connacht).