The National Super Alliance (NASA) co-principal Moses Wetang'ula has said that the Opposition will only accept results if they are credible.
Speaking after casting his vote in Makhele Primary School, Mr Wetang'ula said that the Opposition would not accept results if they felt there was any irregularity in the polling exercise.
He said that they were ready to go to court if the process did not meet the credibility threshold.
"We want nothing short of a win and we will not accept results if we feel the process was not properly conducted and we will move to court with immediate effect to ensure that we have a proper election," he said.
NASA has five co-principals including presidential candidate Raila Odinga, his running mate Kalonzo Musyoka, Musalia Mudavadi, Isaac Ruto and Wetangula.