Museveni cast his vote 30 minutes to the closure of the voting process.
Speaking after casting his vote at Karo Secondary School polling station, Rushere, Museveni called for free and fair elections.
President Museveni also asked Ugandans to maintain peace during the vote-counting process.
Long queues are being seen across Kampala, Uganda’s capital, and across the East African country on Thursday as over 18 million voters turn out to vote in an election that experts are calling “a generational contest.”
Out of nine candidates in the run, the man posing a serious challenge to the incumbent president is Bobi Wine.
Popstar-turned-politician Robert Kyagulanyi Ssentamu, popularly known by his stage name Bobi Wine, is the main opposition candidate hoping to oust President Yoweri Museveni, who has held power since 1986.
Seeking a sixth term in office, Museveni, 76, changed the law in 2017 to scrap a presidential age limit of 75.
The voting began at 7 a.m. (0400GMT) at thousands of polling stations across the country, in events broadcast live by news organizations.
People started queuing up as early as 5 a.m. but most centers reported transportation delays and started polling at 8 a.m.
Biometric voting machines are being used at 34,000 polling stations. Once past the biometric verification, voters are directed to three ballot boxes to vote for their district level, parliamentary, and presidential candidates.
In terms of COVID-19 measures, most voters could be seen wearing masks, but the long queues ignored social distancing protocol.
Hope for peace
Speaking to Anadolu Agency by phone from the Magere Freedom Square polling station, voters called for peace, saying they hope the violence in the country will end.
“I have already voted and I am going home to wait for the results. I am asking my countrymen to respect the majority votes, and not cause violence and deaths as we witnessed in November,” Nancy Namono said.
Hassan Khannenje, the director of the HORN International Institute for Strategic Studies in Nairobi, the capital of neighboring Kenya, said: “Museveni is fairly popular among the population, especially among the rural folk that comprises more than 70% of Uganda’s population.”
He added: “There hasn’t been any credible opinion poll because of the security challenges and also because institutions in Uganda have not been developed sufficiently to do that.”
This is a generational contest between the young and the old and a cultural clash between rural and urban dwellers, he argued.
The internet and social media apps have been shut down to maintain calm and avoid any untoward situation in the country, which saw a surge in violence in the run-up to the election.
The US withdrew as a poll observer over lack of accreditation for its officers by the electoral commission.