Mr Odinga withdrew his participation in the re-run election because he said the electoral commission had refused to implement changes to correct the problems he blames for the bungled election.
The Supreme Court had annulled President Uhuru Kenyatta's win in the August election, after it found that the election commission had not followed the constitution and the electoral laws. Odinga demanded deep reforms that the election commission (IEBC) said were impossible to deliver in the constitutionally mandated period.
A regional and trade gateway, Kenya is East Africa's richest economy and an important Western ally in the fight against militant Islamists in the region.
Odinga, who successfully challenged the August 8 re-election of President Uhuru Kenyatta last month, said the repeat poll should be canceled and a fresh election held after the election board has carried out reforms.
Odinga told Reuters that he might consider returning to the Supreme Court for clarification on whether the October 26 poll was legal. "We must respect the law", he said.
Odinga's withdrawal had fueled speculation about whether the vote would go ahead at all.
Kenyatta's Jubilee Party has pursued changes to the electoral law that the opposition says will make it more hard for the Supreme Court to nullify a presidential election and will reduce safeguards against electoral fraud.
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We don't have another player with the same characteristics. 'We only have [Tiemoue] Bakayoko and [Cesc] Fabregas available'. If I can, I prefer to not change a lot as you find a solution and you lose something with the defence", Conte said.
"We can not go on this way".
In 2013, Kenyatta defeated Odinga in a hotly contested election. Odinga's decision is likely to set the stage for more court battles, while deepening a political crisis that has also led to an economic slowdown.
The standoff over the elections has sparked demonstrations, but the numbers of protesters has tended to be in the hundreds rather than the thousands.
Kenya's government has banned demonstrations in three major Kenyan cities - the capital Nairobi, Mombasa and Kisumu.
In a statement, Kenya's Interior Minister said the ban on protests was put in place Thursday because the demonstrations present a "clear, present, and imminent danger". "I support the exercise of their fundamental right".
"(The government) are talking about a benevolent dictatorship - we can assure them that the people of Kenya will not take it lying down", Odinga said.