According to the Daily Star, Sir Alex Ferguson has made the Croatian playmaker his top summer transfer target.
Fergie has been a huge fan of the 26-year-old for some time and sees Modric as an ideal replacement for Paul Scholes.
Modric was a target for United last summer and Spurs drew up a long-term £100,000-a-week deal for their star player, although it has yet to be signed.
Having failed in an attempt to bring Wesley Sneijder to Old Trafford, Paul Scholes returned from retirement to help with the midfield crisis at the club.
Modric could cost United around £40million, but they may also face competition from Manchester City and Chelsea, especially if Tottenham fail to make the Champions League.