The duo join a five-strong Catalan contingent headed by Ballon d'Or nominees Lionel Messi and Xavi, while Cristiano Ronaldo is among four Real Madrid stars to make the cut
The United duo have been rewarded following a year which saw Sir Alex Ferguson's side win the Premier League, while the other nine representatives are made up of Barcelona and Real Madrid players.
Reigning world, European and Spanish champions Barca had five players, with Ballon d’Or nominees Lionel Messi and Xavi having been joined in the line-up by Barcelona team-mates Dani Alves and Andres Iniesta.
Meanwhile, Iker Casillas, Sergio Ramos and Xabi Alonso were included alongside their Madrid colleague Cristiano Ronaldo, who was also a Ballon d’Or candidate.
2011 Fifa/FifPro World XI: Iker Casillas; Sergio Ramos, Gerard Pique, Nemanja Vidic, Dani Alves; Andres Iniesta, Xavi, Xabi Alonso; Cristiano Ronaldo, Wayne Rooney, Lionel Messi.