The election is providing a stiff test for the west African nation whose reputation as a haven of stability has been marred by weeks of riots over 85-year-old Wade’s candidacy that have left six people dead.
The incumbent was greeted by a cacophony of boos and jeers which drowned out the clapping of a few dozen supporters at the polling station in the suburb of Point E where he owns a private home.
Visibly angry, a tense Wade pushed one of bodyguards out of the way as he beat a swift retreat after voting, without speaking to the media.
Wade circumvented a two-term limit he himself worked into the constitution to run in the election, prompting the country’s worst riots since independence.
He has dismissed the opposition protests as “temper tantrums”.
“My majority is so overwhelming that I think I will be elected with a strong percentage in the first round,” Wade said in an interview with the French newspaper Journal du Dimanche published Sunday.
He heaped derision on calls from France and the United States that he retire, saying his former allies had criticised him because “I am not docile … I am not a Negro service boy”.
Despite the violence, long lines of voters waited patiently to cast their ballots, which European Union observer chief Thijs Berman described as heartening.
“I spoke to many Senegalese who are worried about the process, more worried than usual in Senegal,” he said.
Many are concerned about further violence as results filter through. Partial results will start being published from Tuesday, with a final result known by Friday.
Just days before the poll it emerged more than 450,000 voters cards had yet to be collected, and Berman said it was regrettable that between three and eight percent of about 5.3 million registered voters would not cast their ballots.
The African Union’s envoy, former Nigerian leader Olusegun Obasanjo, said he was pleased with the voting process by midday, saying he believed “we may have a peaceful and honest election”.
An opposition leader for 25 years, Wade’s election 12 years ago was met with euphoria but his efforts to cling to power and line up his unpopular son Karim to succeed him have dented his popularity.
Growing frustrations over high unemployment, rising food prices and crippling power cuts also have Senegalese jockeying for a change in leader.
However the election is cloaked in suspense as Wade takes on 13 opposition candidates, none of whom have emerged a frontrunner.
They include three former prime ministers, Macky Sall, Idrissa Seck and Moustapha Niasse, and Socialist Party leader Ousmane Tanor Dieng.
In a polling station in central Dakar, its walls brightly painted with cartoon characters, Cheikh Angai rooted for a Sall victory.
“He will win, no problem. He is a dignified and serious man. Wade is too old, he has done a good job but now he must leave,” he said.
Amadou Ndiaye, 62, said he hoped for a change from Idrissa Seck, Wade’s former protege and prime minister before a bitter falling-out.
“The president will try to steal the election, but still, one must vote. The old man must leave.”
Wade argues that 2008 constitutional changes extending term lengths from five to seven years allow him to serve two more mandates.
A win would mean Wade would leave office aged 92 in a nation where the median age is 18. He is currently Africa’s second oldest leader after Zimbabwe’s Robert Mugabe, 88.
Wade’s supporters praise him for overseeing a development boom, but he is accused of focusing on prestige projects and being out of touch with the needs of the people.
“Wade will be elected in the first round, I am sure and I wish for it,” said a man in his 50s dressed in flowing blue robes.
“The protests against his candidacy are just political manipulations.”
Analysts say Wade needs to win in the first round while the opposition field is divided, as he would fare less well in a two-horse second round.
The former French colony of some 13 million people is one of the continent’s pioneer democracies, boasting an unbroken series of elections since independence in 1960. Unlike many of its troubled neighbours it has never suffered a coup.