The midfielder, who joined the Gunners from Barca as a 16-year-old in 2003, will now have a further test before agreeing personal terms.
Arsenal announced on Sunday evening they had agreed in principle to grant Fabregas his dream move and bring an end to the long-running transfer saga.
Happy Campers: Cesc Fabregas will join Lionel Messi at Barcelona
How the deal will be doneFabregas will have a medical at 8am at Barcelona Hospital
He will have a further test at 10:30am at Barca's medical centre
The midfielder will sign his contract at 12:30pm with a press conference scheduled for 2pm
All times are local - Spain is one hour ahead of the UK
Thousands of fans of the Spanish champions turned out to welcome Fabregas, who was set to have a second medical examination on Monday before signing his contract and being introduced at a press conference.
Arsenal manager Arsene Wenger told his club's official website: 'We have been clear that we didn't want Cesc toleave and that remains the case.
'However, we understand Cesc's desire to move to his home town club and have now accepted an offer from Barcelona. We thank Cesc for his contribution at Arsenal and wish him future success.'
Fabregas has been agitating for a move to Barcelona for the past two summers and the agreement brings to an end the most high-profile transfer saga of the close season.
A deal for the 24-year-old looked imminent when he was omitted from the Arsenal squad for Saturday's match at Newcastle.
Fabregas, who has won 58 caps for Spain, winning Euro 2008 and the 2010 World Cup, made 303 appearances for the Gunners, scoring 57 goals.
They've got him: Cesc is poised to return to his boyhood club
He was named the club's captain in November 2008.
Fabregas is set to be followed out of the club by fellow midfielder Samir Nasri, who is expected to join Manchester City.
His departure will increase the pressurefrom fans on Wenger to use some of the transfer fee to bring in a big-name signing before the end of the transfer window.
Arsenal exit: Fabregas will fly to Barcelona on Monday to complete the deal
Fabregas had, officially at least, been struggling for match fitness because of a hamstring injury which saw him miss the club's Asia Tour and other pre-season games.
Wenger consciously omitted his captain from the Emirates Cup and the World Cup winner was not selected for Saturday's opening Barclays Premier League fixture at Newcastle, which ended goalless and saw summer signing Gervinho sent off.
However,despite winning both the European Championships and World Cup with Spain, club success has not followed for the midfielder, who missed the Gunners' shock Carling Cup final defeat at Wembley through injury.
Home boy: Fabregas had been agitating for a return to Barcelona
Wenger, meanwhile, will face the media ahead of Arsenal's crunch Champions League play-off against Udinese, which were Fabregas to have played would have made him ineligible for any other club later in the competition.
The Gunners boss will now be under more pressure to spend the proceeds of the Fabregas sale - and indeed the Emirates Stadium coffers could yet be swelled further should contract rebel Nasri also move on.
Thumbs up: Fabregas has played his last game for Arsenal
Wenger, though, has already ruled out a swoop for Juan Mata from Valencia, but could yet look to push through a ?15million deal for Shakhtar Donetsk's Brazilian midfielder Jadson.
Nasri will not be available for the first leg of the Udinese tie because of UEFA disciplinary sanctions, which also mean Wenger must serve a touch-line ban following the fall-out from their Champions League exit in Barcelona last season.
Striker Robin van Persie, likely to be the new permanent Arsenal captain, will also be suspended after his red card in the Nou Camp.
Midfielder Alex Song, meanwhile, could yet find himself on a charge from the Football Association for appearing to stamp on Newcastle midfielder Joey Barton, an incident which was missed by referee Peter Walton during Saturday's ill-tempered game at St James' Park.
Barcelona anticipate no late hitches and have announced details of how Fabregas will seal his return to the club on Monday.
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