Lithuania is to hold presidential elections, with incumbent Dalia Grybauskaite widely predicted to secure her second term, BBC reported.
Recent opinion polls gave her a big lead over her closest rivals: lawmaker Arturas Paulauskas and European Parliament member Zigmantas Balcytis.
She is hoping to secure more than 50% of the votes to avoid a run-off.
The election comes amid rising security concerns in the region after Russia's annexation of Crimea from Ukraine.
"Europe must understand that Russia is trying to redraw the post-war map and borders," Ms Grybauskaite, 58, said recently.
"First, it's Ukraine, Moldova will be next and, finally, it can reach the Baltic states and Poland. This is serious threat to our region."
Polling stations across the Baltic state will open at 04:00 GMT and will close at 17:00 GMT.
Some 2.5m people are eligible to cast their ballots.
With Mrs Grybauskaite seen by many as a hot favourite, critics say the campaigning lacked energy.
"I have never seen in any country such a dull election campaign," former President Valdas Adamkus was quoted as saying by the Associated Press news agency.
First results are expected shortly after the voting ends.