Pujols received 32 first-place votes, two from each NL city, in the balloting of the Baseball Writers Association of America. He is the ninth unanimous selection and the first since Scott Rolen of Philadelphia in 1997.
Not much more than an afterthought entering training camp, the 21-year-old Pujols spent most of the 2000 season in Class A but earned a job when the club broke camp by displaying versatility and a potent bat.
"I reached my goal to make the big leagues. I worked hard every day," Pujols said. "Tony (manager Tony La Russa) but the trust in me and gave me the chance. I'm just blessed."
And the production and versatility carried over into the season as Pujols batted .329 with 37 homers and 130 RBI while playing games at first and third base, left and right field. The RBI were a NL rookie record while Pujols led the wild card champions in average, homers, runs (112), hits (194) and doubles (47).
"It doesn't matter (where I play)," Pujols said. "I'm just going to spring training and trying to make the team again."
In addition to the RBI record, Pujols also set league rookie records for extra-base hits (88) and total bases (360). He is just the fourth rookie in major league history to hit .300 with 30 homers, 100 RBI and 100 runs.
Pujolis is the sixth Cardinal to win the award and first since reliever Todd Worrell in 1986.
"I'm so happy to get this award. You only can get it one time," Pujols added.
Pujols also is in line to receive Most Valuable Player consideration and already has been awarded the Silver Slugger Award for production at third base.
Houston Astros righthander Roy Oswalt was second and Philadelphia shortstop Jimmy Rollins was third in the voting, which took place at the end of the regular season. Oswalt went 14-3 with a 2.73 ERA this season and was even better as a starter, going 12-2. Rollins batted .274 with 14 homers, 54 RBI and 46 stolen bases.