Ali followed her father into the boxing ring and is the unbeaten International Boxing Association super-middleweight champion.
Commenting on the deal, Ali said one of the reasons she supported the brand was because of its commitment to boxing.
She said: "I am very excited and proud to be aligned with a brand that is a part of boxing's great history, and continues to support boxing's future and athletes that are committed to achieving their personal best through sports."
Few details of the contract were available. However, it has been reported that she will appear in the brand's integrated marketing drives throughout 2005.
Erich Stamminger, Adidas-Salomon executive board member responsible for global marketing, called Ali an inspiration.
"It is very exciting to have such a powerful and talented female athlete as part of the Adidas brand," he said. "Laila is an inspiration to women and all athletes that aspire to break new ground."
The value of the deal was undisclosed.
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