Guinea's 82-year-old President Alpha Conde is seeking reelection after a change in Guinea's constitution allowed for him to run for a third term.
Mr Conde, who has described the constitutional reform that allowed him to run again as fair and democratic, says he needs more time to finish major mining and infrastructure projects in the West African country.
Sunday's vote will be the third match-up between Conde and his long-time rival Cellou Dalein Diallo, whom he defeated in 2010 and 2015.
If he fails to win with more than 50% of the vote, the president will probably have to face off against Diallo.
Conde has lead Guinea for the last 10 years. He came to power in 2010 in the West African nation's first democratic elections since independence from France in 1958.
Guinea has made progress developing its mineral riches, including bauxite and iron ore, and gross domestic product has doubled under Conde’s presidency.
As one of the three countries severely affected by West Africa's 2014-16 Ebola outbreak - alongside neighbouring Sierra Leone and Liberia - Guinea developed experience in tackling infectious disease that it has been able to bring to bear in its response to the Covid-19 pandemic.
The electoral campaign in this West African nation already has seen deadly protests, which some fear could explode after results are announced. More than 50 people have been killed in anti-Conde protests since October last year.
The International Criminal Court at The Hague has said it is “deeply concerned” about the mounting tensions.
In recent days, opposition supporters have clashed with ruling party activists in northern Guinea, leaving dozens injured.