Giovanni Trapattoni's reign as manager is over after defeat in Austria on Tuesday effectively ended Ireland's hopes of World Cup qualification.
Who's next in line for the Ireland hot-seat?
Former Sunderland boss O'Neill is available after being shown the door at the Stadium of Light in March. The 61-year-old Northern Irishman has already been installed as the bookmakers' favourite, although it is understood he had not been contacted before Tuesday's 1-0 defeat at the Ernst Happel Stadion.
It was McCarthy who took Ireland to the 2002 World Cup finals in the Far East, where then skipper Roy Keane's differences with the Republic set-up infamously came to a head. The current Ipswich boss had more than six years in charge of the country for which he played, and like O'Neill, the 54-year-old would enjoy popular support if he was appointed.
Hughton, 54, remains a hugely popular figure in Ireland, for whom he won 53 senior caps. An accomplished coach, he has established an enviable reputation as a manager after first stepping into the limelight at Newcastle, whom he guided back into the Barclays Premier League following relegation, and has impressed at both Birmingham and current club Norwich since. However, he has distanced himself from the job, stating he is happy to remain with his club.
For many, Keane would be the perfect man to shake things up with his no-holds-barred approach to the game. Currently working as a television pundit, the 42-year-old Cork man cut his teeth as a manager at Sunderland, winning promotion to the Premier League at the first attempt, and later guided Ipswich to the semi-finals of the Carling Cup.
TRAPATTONI'S MANAGERIAL RECORD
Giovanni Trapattoni repeatedly insisted results would provide the evidence of his success or otherwise as Ireland manager.
P64, W26, D22, L16
WORLD CUP QUALIFIERS
P18, W7, D8, L3
WORLD CUP PLAY-OFFS
P2, W0, D1, L1
EUROPEAN CHAMPIONSHIPS QUALIFIERS
P10, W6, D3, L1
EUROPEAN CHAMPIONSHIPS PLAY-OFFS
P2, W1, D1, L0
EUROPEAN CHAMPIONSHIPS FINALS
P3, W0, D0, L3
CARLING NATIONS CUP
P3, W3, D0, L0
P26, W9, D9, L8 120450 SEP 13
GIOVANNI TRAPATTONI FACTFILE
1939: Born, 17 March in Cusano Milanino.
1959: Signed as a defender by AC Milan.
1962: Wins first Scudetto as a player with AC Milan.
1963: Part of the AC Milan side which wins the European Cup for the first time with a 2-1 win over Benfica.
1960: Represents the Italian football team at the Olympics in Rome.
1962: Plays for Italy at the World Cup in Chile.
1967: Wins Serie A and Coppa Italia double with AC Milan.
1968: Lifts European Cup Winners' Cup with AC Milan.
1969: Collects second European Cup winners medal with AC Milan.
1971: Makes last of 387 professional appearances for AC Milan before he signed for lower league side AS Varese.
1972: Retires from playing.
1974: Appointed youth team coach at AC Milan.
1975: Made AC Milan first-team coach and his team finish as runners-up in the Coppa Italia.
1976: Appointed Juventus coach.
1977: Steers Juventus to a Serie A and UEFA Cup double.
1978: Claims consecutive Serie A title with Juventus.
1979: Juventus win Coppa Italia.
1981: Wins third league title with Juventus.
1982: Delivers fourth Serie A title as Juventus boss.
1983: Wins second Coppa Italia for Juventus.
1984: Takes fifth Serie A title to Turin and wins the European Cup Winners Cup with a 2-1 win over FC Porto in Basel.
1985: Manages Juventus to a 1-0 European Cup victory over Liverpool but the match is overshadowed by disaster off the pitch at the Heysel Stadium.
1986: Wins sixth Serie A title with Juventus before he returning to Milan to manage Inter Milan.
1989: Inter win Serie A title under Trapattoni.
1991: Guides Inter to a 2-1 aggregate UEFA Cup final victory over Roma before he returns for a second spell at Juventus.
1994: Finishes twice as Serie A runners-up with Juventus before leaving to join Bayern Munich.
1995: Returns to Serie A for a brief period in charge of Cagliari.
1996: Second spell with Bayern Munich.
1997: Leads Bayern to Bundesliga title.
1998: Bayern finish runners-up in the Bundesliga but win the domestic cup.
June: Returns to Serie A to manage Fiorentina.
2000: Replaces Dino Zoff as Italy manager.
2002: Leads Italy to the World Cup in Japan and South Korea. Italy suffer a surprise second-round exit at the hands of South Korea. Trapattoni is blamed for an overly-defensive brand of football and not taking Roberto Baggio.
2004: June: Italy are knocked out of Euro 2004 in Portugal at the group stage on goal difference after draws against Denmark and Sweden and a victory over Bulgaria.
July: Contract with Italian FA not renewed and Trapattoni is named coach of Benfica.
2005: Ends Benfica's 11-year wait for the Portuguese league title but resigns at the end of the season to take the coach's position at Stuttgart.
2006: February: Sacked by Stuttgart after 20 games in charge.
May: Austrian side Red Bull Salzburg appoint Trapattoni as director of football with former Germany international Lothar Matthaus as first-team coach.
2008: 11 February - Agrees in principle to take over as Republic of Ireland manager.
24 May - First game in charge is a 1-1 draw with Serbia.
2009: September: Signs a new contract through to 2012.
18 November - Presides over the World Cup play-off loss to France, which is decided after Thierry Henry's handball controversy.
2011: Guides Ireland to Euro 2012 with a play-off win over Estonia.
2012: Given a new two-year contract.
June - Ireland disappoint at Euro 2012, losing group games to Spain, Italy and Croatia.
October - Ireland lose a World Cup qualifier 6-1 to Germany.
2013: 11 September 11 - After back-to-back defeats against Sweden and Austria leave the Republic out of contention to qualify for the 2014 World Cup, Trapattoni leaves his post as Republic manager. His departure is by "mutual consent", the Football Association of Ireland announce.
Press Association Sport