The committee has been investigating alleged breaches of its code of ethics by Adamu since March 2015.
It recommended a two-year ban and a fine in December.
Adamu was a former FIFA executive committee member for four years, before his initial suspension for three years in 2010. The 62-year-old was found guilty of asking for money in exchange for World Cup votes, an accusation he denied.
“The adjudicatory chamber of the independent Ethics Committee, chaired by Hans-Joachim Eckert, has decided to ban the former football official Amos Adamu for two years from taking part in any kind of football-related activity at national and international level,” FIFA announced in a press release on Tuesday.
“The investigation into Mr Adamu was conducted by Dr Cornel Borbély, chairman of the investigatory chamber of the Ethics Committee, which resulted in a final report being submitted to the adjudicatory chamber on 2 December 2016. Adjudicatory proceedings were formally opened on 20 December 2016.
“The adjudicatory chamber determined that, through his involvement in the organisation of an event in 2010, while being a member of the (then) FIFA Executive Committee, Mr Adamu violated articles 13 (General rules of conduct), 15 (Loyalty) and 19 (Conflicts of interest) of the FIFA Code of Ethics.
“The sanction is effective from 28 February 2017, the date on which this decision was notified.”