Chileans are voting in presidential elections to choose a successor to Michelle Bachelet. Eight candidates are standing, with conservative billionaire Sebastián Piñera seen as favourite to return to the post he held from 2010-14.
Socialist contender Alejandro Guillier, a former journalist, is regarded as the most realistic challenger to Mr Piñera.
On Sunday, voters are also electing all 155 members of the lower house and half of the senate.
Mr Piñera, 67, has been leading in recent opinion polls. However, analysts say he may fail to get 50% of the votes needed to avoid a run-off in December.
