He was initially credited with boosting the nation's infrastructure, but his critics have accused him of autocracy and said he is grooming his son to take over after him.
Others have accused the leader of grandiose investments, including a costly towering monument near the capital of Dakar that sparked criticism in a country where poverty is still rife.
Other contenders include Ousmane Tanor Dieng, Moustapha Niasse and Macky Sall, the latter of whom considered Wade a mentor.
Wade is among a list of elderly leaders clinging to power in sub-Saharan Africa despite demands for them to step down. Zimbabwean Presidentused his recent 88th birthday to lash out at critics and vowed to run for re-election.
The opposition has said it will protest if Wade wins, but analysts say a lack of cohesion among foes and a system that favors the incumbent make it harder to unseat Wade, who is nicknamed the "hare" for his shrewd politics.