Voters in the mountainous Central Asian republic of Kyrgyzstan are electing a new president.
Hopes are that the poll will help end the current political instability
The poll comes five months after the ousting of the long-serving Soviet-era leader Askar Akayev, who fled after a wave of opposition protests.
Six candidates are running, but acting president Kurmanbek Bakiev is widely expected to win.
The BBC's correspondent in Bishkek says that the election campaign has been lacklustre and hardly visible.
The candidates have addressed some campaign meetings and they have appeared on live televised debates answering questions from the public - a first for Central Asia.
But there is little indication on the streets of Bishkek that the nation is about to choose its first post-Soviet president, says the BBC's Ian MacWilliam.
The authorities' most immediate concern is a possible low turnout - more than 50% must vote for the result to be valid. Kyrgyzstan is also experiencing a heat wave with temperatures topping 40C (104F).
The demonstrations that eventually drove Mr Akayev into exile were triggered by disputed parliamentary elections in February and March.
The impoverished republic has been racked by protests ever since.
However, most political observers say there have been few serious abuses of the electoral law in the run-up to Sunday's poll.
At stake is Kyrgyzstan's relationship with the US.
Kyrgyzstan has a US and a Russian military base on its territory, but after the poll the new government will have to decide whether to continue hosting the US base.
The country's neighbours, Russia and China, are making it increasingly clear they want to limit the US presence in Central Asia.