All 140 MLAs turned up to cast their vote, sources in the legislature secretariat said.
The results are expected to be out by the the evening.
The election has assumed political significance mainly
The rebel, Kodoth Govindan Nair, has been expelled from the party for six years for his refusal to pull out of the fray in favour of the official nominees, Vayalar Ravi and Thennala Balakrishna Pillai.