Long queues of voters were seen in urban as well as rural areas as polling proceeded in a peaceful manner.
According to Election Commission, 6.9% voter turn out was recorded in the first hour itself.
Contestants and leaders of various political parties were among the early voters in different constituencies, especially in the state capital.
Defence Minister A K Antony cast his vote in a booth in Thiruvananthapuram. Chief Minister Oommen Chandy and his family members voted in their home segment in Pudupally in Kottayam district.
A total of 21,424 polling stations had been arranged for 2.42 crore electorate in the state, which has a reputation for high voter turnout in the past elections.
Though 269 candidates are in the fray, the main fight, as in the past, is between the Congress-led UDF, now in power, and the opposition CPI(M)-led LDF.
The BJP has turned the electoral battle into a three-horse race in the state capital in down south and the northernmost Kasargode.