Lusaka - The front-runners in Zambia's presidential election on Thursday are incumbent Edgar Lungu and rags-to-riches businessman Hakainde Hichilema - two adversaries who battled it out only last year.
Lungu won that election by fewer than 28,000 votes, securing the right to complete the final months of the term of his predecessor who died in office.- Edgar Lungu -
Lungu, 59, is a trained lawyer who emerged as the unlikely victor of a bruising struggle to lead the Patriotic Front (PF) party after the death of president Michael Sata in 2014.
Previously a low-profile defence and justice minister, he has used his short time in power to present himself as the rightful heir to Sata, who enjoyed widespread popularity.
Demonstrating his tough streak, Lungu has given angry campaign speeches, vowing to "sacrifice democracy for peace" to preserve Zambia's relative stability.
But he has taken over at a tricky time for the Zambian economy, as the price of copper - the country's key export - has fallen sharply, and he faces a difficult election.
Lungu was born in 1956 in Chadiza in eastern Zambia and is from the minority Nsenga ethnic group, often describing himself as a non-tribal Zambian from an ordinary background.
He graduated with a law degree from the University of Zambia in 1981 and also underwent training as a military officer.
Lungu cut his political teeth at the United Party for National Development (UPND), but in 2001 he quit to form the PF with Sata.
After the PF first came to power in 2011, he rose to be home affairs minister.
Also read: Zambia at a glance - ahead of elections
On social issues he revealed a conservative side after the arrest of two Zambian gay men in 2013.
"Those advocating gay rights should go to hell," he said. "That issue is foreign to this country."
After two previous presidents died in office, his health has been in focus.
He suffers from recurring achalasia, a condition caused by narrowing of the oesophagus, and was flown to South Africa for treatment last year after collapsing in public.
He is married, with six children, and is now a grandfather.- Hakainde Hichilema -
Hakainde Hichilema, 54, who represents the United Party for National Development (UPND), is a self-made entrepreneur making his fifth attempt at the Zambian presidency.
Known as "HH", he alleged that the 2015 election was stolen from him by fraud, although he appealed to his supporters to stay peaceful.
Now he expects to succeed at last, despite accusing the authorities of undermining his campaign by banning rallies and allowing violent attacks on his activists.
An articulate speaker, Hichilema has drawn large crowds to his rallies, run a slick social media campaign and worked hard to shed his image as an elitist lacking the common touch.
He was born to a poor family in the southern district of Monze, but says his "grit and determination" at school won him a priceless scholarship to the University of Zambia where he graduated in 1986 in economics and business administration.
He then took at MBA degree at the University of Birmingham in Britain.
He started off small, buying and selling houses, eventually becoming one of the country's richest businessmen with major interests in finance, ranching, property, healthcare and tourism.
At the age of 32, he was Zambia CEO of Coopers and Lybrand consultancy accountants, and he has sat on the boards of several large Zambian corporations.
Hichilema has promised to build a business-friendly Zambia and attract investment, while at the same time pledging to alleviate hardship among the country's millions of poor.
On his campaign website he describes himself as a "Christian and a philanthropist" who funds clinics, schools, boreholes and dam building.
His campaign slogan has been "HH will fix it", although many of his posters in Lusaka have been vandalised.
He is married and has a daughter and two sons.