"We have been cooperating, and will continue to cooperate, with the authorities," the company said, after the US Justice Department indicted 14 FIFA officials and sports marketing executives over bribery.
Nike was neither directly named nor accused in the case.
But one of the indictments, against Brazilian sportsmarketer Jose Hawilla and his Traffic Group, charged that Hawilla paid kickbacks to a senior Brazilian and FIFA soccer official after arranging in 1996 for an unnamed major US sportswear company to sponsor Brazil's national soccer federation and national team.
Nike gave no details on how it is involved in the case announced by the US Justice Department today.
"Like fans everywhere we care passionately about the game and are concerned by the very serious allegations," the company said.
"Nike believes in ethical and fair play in both business and sport and strongly opposes any form of manipulation or bribery.