The Premier League duo drew 2-2 last Sunday, resulting in a replay.
A FA statement read: "Following consultation with all relevant stakeholders, The FA can confirm that The FA Cup with Budweiser Sixth Round Proper Replay between Chelsea and Manchester United at Stamford Bridge will take place on Easter Monday 1 April, live on ITV. Kick-off is at 12.30pm."
Chelsea came from two goals down to draw 2-2 with the Premier League leaders at Old Trafford last Sunday. The winners will play Manchester City in the semi-finals.
The replay has imposed a busy schedule on the West Londoners, who said a league match scheduled at Southampton on March 31 would now be played on March 30 instead.
The European champions are also still in the Europa League and have a last 16 second leg at home against Steaua Bucharest on Thursday that could lead to a quarter-final first leg on April 4.