Balloting for the Lakshadweep Lok Sabha seat, with an electorate of less than 50,000, began Thursday.
India's smallest union territory Lakshadweep is a group of 36 islands.
Just six candidates are in the fray.
Forty-three polling booths have been set up for the voting that began 7 a.m., officials said.
The Congress has dominated Lakshadweep ever since its first Lok Sabha elections in 1967, except for the 2004 polls when the Janata Dal (United) won.
Sitting Congress MP Hamdullah Sayeed, 31, is the youngest member of the 15th Lok Sabha.
It is for the first time that Communist Party of India is fielding a candidate - Najmudheen C.T. - from this Scheduled Tribes reserved constituency.
The remaining five candidates in the fray are: Abdul Muneer of the Communist Party of India-Marxist, Mohammed Faizal P.P. of the National Congress Party, M.P. Sayed Mohammed Koya of the Bharatiya Janata Party (BJP), Hamdullah Sayeed of the Congress, and Samajwadi Party's Komalam Koya.