United are the team to catch in the race for the Premier League and bagged five wins during the month over Fulham, Derby, Bolton, Liverpool and Aston Villa.
Ronaldo scored the winner against Derby, both goals in the 2-0 victory over Bolton and made another goalscoring contribution in the 3-0 demolition of Liverpool.
His backheel against Villa took his season tally to 27 Premier League goals and it’s the fourth time he has won the monthly award.
Ferguson has been named manager of the month 21 times since his first gong in August 1993.
And Ronaldo is also the hot favourite to win the PFA Player of the Year award for the second year running, with the nominations announced earlier on Friday.
The 23-year-old Manchester United star – who is also in the running for young player of the year – has enjoyed another outstanding season, spearheading his side’s push for glory in both the Premier League and the Champions League.
Other players up for the award are Arsenal pair Cesc Fabregas and Emmanuel Adebayor and Liverpool striker Fernando Torres.
Liverpool skipper Steven Gerrard and veteran Portsmouth keeper David James are the other nominees.