She was first elected president in 2015, shortly after Nepal's post-war constitution was passed, which carves out one-third of seats in parliament for woman and mandates that either the president or vice president must be a woman.
Bhandari defeated her Nepali Congress (NC) rival Kumari Laxmi Rai.
Nepal's parliament on Tuesday re-elected Bidhya Bhandari as the country's president, three months after parliamentary polls were held.
An electoral college, including members of parliament and provincial assemblies, will vote in the election.
The UML and its coalition partner, the former rebel Maoists, enjoy almost two-thirds majority in the parliament, which assured Bhandari's victory. The votes of federal and provincial lawmakers were given different weightage.
Federal Socialist Forum Nepal, Rastriya Janata Party Nepal, and other fringe parties had also backed Bhandari.More news: Kerala bans trekking in forests after Theni wildfire tragedy
The voting which begun from 10 a.m.in the office of the Election Commission of Nepal (ECP) in Kathmandu ended at 3 p.m.
Bhandari mustered 39,275 votes while Rai garnered 11,730 votes, Election Commission spokesperson Nawaraj Dhakal said. Meanwhile, the counting of votes started at 4:00 pm following the conclusion of ballot casting.
With 148 lawmakers in the Federal Parliament and 243 in Provincial Assemblies, the CPN-UML commands a total vote of 23,356.
Bhandari is the first female president of Nepal.
Out of the 334 federal parliament members, 326 members cast their votes in the election. If successful, she will be the first president of Federal Nepal. Likewise, 549 provincial assembly members were eligible to exercise their franchise in the presidential election, of which 13 were absent during the vote casting.