National Assembly Speaker Justin Muturi has declared the Ugenya parliamentary seat vacant.
He wrote to IEBC chairman Wafula Chebukati on September 11 informing the commission of the same.
The speaker invoked Section 101 of the Constitution.
The law states that the speaker shall, within twenty-one days after the occurrence of the vacancy, give notice in writing of the vacancy to the Independent Electoral and Boundaries Commission.
The Constitution states that a by-election shall be held within ninety days of the occurrence of the vacancy.
Muturi's notification to the IEBC followed the Court of Appeal's August 16 ruling which annulled Chris Karan's election.
The latter lost the seat after former MP David Ochieng' challenged his election in the August 2017 vote.
The High court on March 1 ruled that Karan's campaign was "perverted" and that the entire election in Ugenya was "compromised".
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The Court of Appeal later dismissed the legislator's case challenging the High court ruling.
Appeals court's Justice Hannah Okwengu said the election was validly nullified.
Following the declaration, Ugenya residents are expected to hold an election of a new member within 90 days.
Karan contested under ODM party while Ochieng' ran as an independent.
Ochieng' argued that his campaign was hampered after accusations he had a hand in IEBC ICT manager Chris Msando's murder.