The 22-year-old Portuguese winger has been in scintillating form this season, firing 21 goals and setting the Premiership alight with his skill and trickery.
The last player to win both awards was Andy Gray in 1977, and Ronaldo is the first United player to win the senior award since Ruud van Nistelrooy in 2002. He takes the Young Player crown from Wayne Rooney, who has held the trophy for the past two years.
Cristiano collected the award at a gala dinner in London and described it as a "special night".
"It is amazing and a big honour for me to win trophies like this in the English Premier League. I am very proud," he said. "My colleagues have voted for me and that is fantastic because players know the qualities of players.
"I want to keep working hard and getting better because these trophies have now given me more motivation. At this moment, I am consistent. I am more mature now and I am playing better.
"This great team has helped me as well," he said, acknowledging the role of his team-mates, "because when the team win it is easier for us all to play with more confidence."
The prestigious accolades, voted for by fellow professionals, mark a personally good end to a season which began with boos from opposition fans and criticism in some sections of the press for a perceived contribution to England's exit in the quarter finals of the 2006 World Cup in Germany.
He responded in the best possible way, producing some outstanding individual displays, which have made a sizeable contribution to United's current plight - three points clear at the top of the Premiership, in the FA Cup final and about to embark on a Champions League semi final with AC Milan.
Ronaldo is now ranked by many - his manager Sir Alex Ferguson in particular - as the best player in the world, and recently signed a new deal at Old Trafford that will keep him at the club until at least 2012.
Chelsea striker Drogba finished second in the voting for the senior award, while Paul Scholes came third, worthy acknowledgement for his excellent performances this season after recovering from a serious eye injury to be a major influence for the Reds this term.
Arsenal midfielder Fabregas ended up second in the voting for the Young Player award, in front of Tottenham's Aaron Lennon.
United also had a staggering eight players in the 2007 PFA Premier League Team of the Year, as follows: Edwin van der Sar; Gary Neville, Nemanja Vidic, Rio Ferdinand, Patrice Evra; Ryan Giggs, Paul Scholes, Steven Gerrard (Liverpool), Cristiano Ronaldo; Didier Drogba (Chelsea), Dimitar Berbatov (Tottenham). Special Merit Award - Sir Alex Ferguson