The match will be played during the week beginning the 9th September at Cambridge's 9,247 capacity Abbey Stadium.
As the Royals pushed onto victory after victory last season in Division Two Cambridge couldn't get a win for love nor money which meant they ended up bottom of the pile. They will kick off the new campaign in Division Three.
Last season the Royals gained a 1-0 victory over the U's at the Madejski Stadium, James Harper the only scorer in a forgetable match. Then back in March the sides played out a 2-2 draw, Cambridge missing a penalty and effectively sealing their relegation.
Ticket information and when the match will kick off should be available shortly.
Elsewhere, the winners of the preliminary round game between Boston and Bristol Rovers will play Cardiff. Brighton are at home to Exeter whilst Stoke travel to Bury.
Meanwhile, the club have already sold 500 tickets for the openign day clash with Derby at Pride Park, the Royals expect to compeltely sell their allocation for the game. Tickets are priced at £20 for adults, OAPS £10 whilst Under 16s can get their tickets for just £1.