He was barred from entering the US and Britain in 2005 because of corruption allegations.
The primaries also brought back three ex-members of the government of Daniel arap Moi, the former president.
Sammy Mwaita, Sally Kosgey and Zakayo Cheruiyot were all nominated for constituencies for the opposition Orange Democratic Movement (ODM) party.
Violence and arrests
Violence, arrests and delays occurred during the primaries, on Friday and Saturday, to select party candidates for December 27 legislative elections.
Gangs and rival party supporters clashed as tens of thousands of polling stations opened, police said.
In the volatile Westlands constituency, in the capital Nairobi, gunshots were fired into the air to scare rival supporters, vehicles were smashed and an election official was briefly kidnapped.
After being released, the official said: "The situation is very tense."
In the Mount Elgon region, near the border with Uganda, armed tribal group members demanded an end to a land distribution scheme and ambushed a vehicle carrying ballot boxes.
They shot and injured seven people, including an election official and at least three policemen, witnesses said.
Police arrested a man wielding a machete and fired tear gas to disperse demonstrators disputing the way some candidates had been nominated in Western Kenya.
A man was also shot in the head and several people were arrested, police said.
Fiasco and disgrace
Kenyan newspapers called the primaries a "fiasco" and a "national disgrace".
The primaries took place for all political parties in Kenya. They were given up to midnight on Saturday to complete the nominations by the electoral commission of Kenya.
The PNU submitted its completed party list on time, but the ODM did not. This was due to nominations in some areas failing to take place due to the electoral chaos.
The presidential elections are shaping up to be the closest yet in the country.
Raila Odinga, leader of ODM, is ahead of Mwai Kibaki, the incumbent president, by about 10 per cent in two polls, while a third shows Kibaki to be ahead by less than one per cent.