The move sees the 28-year-old return to the KC Stadium for a second stint after impressing with five goals in 12 games after joining on a loan deal during the second half of last season.
Gedo's goals were crucial in helping Hull secure promotion to the Barclays Premier League, and manager Steve Bruce will welcome the return of a player who will provide competition to the likes of Yannick Sagbo, Danny Graham and Sone Aluko.
The move, which still awaits formal clearance, will go some way to helping Bruce overcome the disappointment of missing out on West Brom striker Shane Long.
Press Association Sport understands striker Long was given permission to leave the Republic of Ireland's training camp to discuss the prospect of a transfer to East Yorkshire.
The 26-year-old was reportedly at the Tigers' training ground when it emerged Baggies boss Steve Clarke had pulled the plug on the deal as he sweated on reinforcements of his own.
Meanwhile, Hull winger Cameron Stewart has joined Charlton on loan.
The 22-year-old, who began his career at Manchester United, will stay at The Valley until January 2.
Stewart spent time on loan at Burnley and Blackburn last season and he is set to make his Addicks debut against Watford a week on Saturday.
Defender Conor Townsend has also gone out on loan, joining League One side Carlisle on a 28-day deal.