Cristiano Ronaldo will return to Old Trafford for the first time since leaving Manchester United in June 2009, after Real Madrid were drawn with Sir Alex Ferguson's side in the second round of the Champions League.
Barcelona were paired with AC Milan, who they knocked out at the quarter final stage last season.
Group C winners Málaga will face Portuguese champions Porto, while Valencia face Paris Saint-Germain.
Champions League Second Round Draw in Full
Galatasaray vs Schalke
Arsenal vs Bayern Munich
Celtic vs Juventus
Shakhtar Donetsk vs Borussia Dortmund
AC Milan vs Barcelona
Real Madrid vs Manchester United
Málaga vs Porto
Valencia vs Paris Saint-Germain
First legs will be played 12/13/19/20th February, 2013
Second legs will be played 5/6/12/13th March, 2013