Chad is set to become the first of Africa’s current junta-led states to move to democratic rule with Monday’s presidential vote.
It will end a three-year transition imposed after the sudden death of long-serving leader Idriss Déby Itno while fighting rebels.
Prime Minister Succès Masra is among his nine challengers and is seen as his biggest rival.
The start of voting was marked by delays, with polls opening an hour behind schedule in some areas.
President Déby kicked off the exercise by casting his ballot in the capital, N’Djamena.
He expressed pride for having fulfilled his promise to respect the deadline for “elections that will signal a return to constitutional order.”
Activists have called for a boycott of the election that they termed a ploy to lend a sheen of democratic legitimacy to the Déby dynasty.
