Bent, who joined Tottenham for £16.5 million two years ago, was at the Stadium of Light on Monday morning and a deal is expected to be formally completed within the next 24 hours.
Sunderland manager Steve Bruce has been trying to sign the 25 year-old, who has four England caps, for some time but the clubs have been unable to agree a fee.
The impasse now looks to have been broken reportedly for a £12 million fee allowing Bent to finally move and become Sunderland's record signing.
Bent would join England Under-21 striker Fraizer Campbell, who has moved from Manchester United, Albanian midfielder Lorik Cana from Marseille, and Paraguay defender Paulo da Silva as new signings at the Stadium of Light.
The fee would eclipse the £9 million spent by Sunderland on Scotland keeper Craig Gordon who they bought from Hearts.
Bent has been pushing hard for a move from Tottenham to the Black Cats and caused controversy last week by posting an entry on his Twitter account to criticise Spurs chairman Daniel Levy for holding up the move.
He later apologised saying: "I appreciate that transfers are seldom straightforward.
"I regret my actions and did not intend to offend Daniel Levy or anyone with the nature or the content of my posting."
Meanwhile, Tottenham manager Harry Redknapp has rubbished reports that he has submitted a bid for Newcastle defender Sebastien Bassong, although he admitted the defender is a player he is interested in.