Fowles was joined on the five-member squad by Tennessee's Candace Parker, Oklahoma's Courtney Paris, Stanford's Candice Wiggins and Maryland's Crystal Langhorne.
"This is a nice honor to have," Fowles said. "But I owe a lot of this to my teammates. They make me a better player."
The Miami, Fla., native averaged 16.9 points and 12.6 rebounds last season as a junior on her way to first-team All-America honors by the AP, ESPN.com, Kodak/WBCA, the United States Basketball Writers Association and the John R. Wooden Award.
So far in LSU's two exhibition games this year Fowles has posted 17.0 points, 7.0 rebounds and 3.0 blocks per game.
"Sylvia is an outstanding player," LSU head coach Van Chancellor said. "There is no doubt in my mind that she is one of the best players in the country. She is very deserving of this honor. I am very glad she is on our team."
Fowles received 41 votes, while Parker, a unanimous choice for All-American, was on every ballot of the 50-member national media panel. Paris came close to a unanimous selection, getting 48 votes. Wiggins drew 43 and Langhorne 28.
In addition to Fowles first-team AP All-American honor, she has been named preseason first-team All-Southeastern Conference as well as being named as a preseason candidate for the Wade Trophy and the John R. Wooden Award.