Ahead of today's eagerly anticipated match at Wembley, we look at six of the best FA Cup clashes between the two great rivals.
Feb 14, 2004 - Old Trafford
MAN UNITED 4 - MAN CITY 2
The Manchester rivals last met in the fifth round seven years ago when a Ruud van Nistelrooy double helped them to victory. They won despite playing for just under an hour with 10 men after Gary Neville was sent off. United went on to win the cup, beating Millwall 3-0 in the final in Cardiff.
Feb 18, 1996 - Old Trafford
MAN UNITED 2 - MAN CITY 1
Lee Sharpe scored United's winner in the second half to complete a comeback. Uwe Rosler opened the scoring but Eric Cantona's penalty meant the match was level at half-time. The Frenchman scored the only goal in a disappointing final against Liverpool at Wembley.
Jan 10, 1987 - Old Trafford
MAN UNITED 1 - MAN CITY 0
This FA Cup third-round clash was Sir Alex Ferguson's first encounter with his local rivals and Norman Whiteside's second-half goal ensured he would end it on top.
Jan 24, 1970 - Old Trafford
MAN UNITED 3 - MAN CITY 0
One from Willie Morgan and two from Brian Kidd - now Roberto Mancini's right-hand man at City - booked United's place in the fifth round, where they thrashed Northampton 8-2 with George Best scoring six. Their run ended at the hands of Leeds in the semi-final.
Jan 29, 1955 - Maine Road
MAN CITY 2 - MAN UNITED 0
City have to go back more than 56 years for their last success against United in the FA Cup. Joe Hayes and future Leeds and England manager Don Revie scored the second-half goals for the Blues, who went on to lose to Newcastle in the final.
Mar 21, 1926 - Bramall Lane
MAN CITY 3 - MAN UNITED 0
Tommy Browell scored twice for City inside the first half-hour in Sheffield to book their place in the final, but Bolton claimed the Cup with a solitary goal from David Jack at Wembley Stadium in London. It was a strange season for City, who also enjoyed a 6-1 league success against United but were relegated to Division Two.