Sky Sports revealed last month that Fulham had made an opening bid of £5million for the 27-year-old striker, who was top scorer in the Championship last season with 29 goals.
Fulham returned to the table with a new bid last week, and following lengthy negotiations, the two clubs have now agreed a deal believed to be worth around £11million.
McCormack will now sign a four-year deal with the Cottagers, ahead of linking up with them at their pre-season training camp in his native Scotland.
Leeds owner Massimo Cellino had insisted he did not want to sell McCormack, but he finally agreed to sell in the early hours of Tuesday morning.
Does this mean that the Leeds squad can stop doing their own laundry?- doctor_cowboy