He topped the writers' poll ahead of Liverpool striker Fernando Torres and Portsmouth goalkeeper David James.
The 23-year-old, who has scored 38 goals in all competitions this season, emulated the feat of Barcelona's former Arsenal striker Thierry Henry -- the last man to collect the FWA award twice in a row, in 2003 and 2004.
"Ronaldo's award is no surprise after his brilliant form this season and incredible goal-scoring record -- 38 at the moment -- and he is, of course, essentially a winger," said chairman of the FWA,
"Cristiano was an overwhelming winner and, given his age, he has the potential and ability to dominate this award for years in an unprecedented way."
Ronaldo has this season has helped take United to within touching distance of a second successive Premier League title with two matches to play, and into a Champions League final against Chelsea in Moscow on May 21.
He will receive his award at the FWA's gala dinner at the Royal Lancaster Hotel in London on May 15.