Constituents of Embakasi South will today elect their preferred representative in the National Assembly.
There are 15 candidates cleared and listed by the Independent Electoral and Boundaries Commission (IEBC) to contest.
The position fell vacant after the Supreme Court revoked Julius Mawathe's win.
The petition was filed by Orange Democratic Movement candidate Sumra Irshad.
Yesterday, IEBC dispatched heavily guarded polling materials to 221 polling stations after a brief training exercise for election observers.
There was calm, with residents expressing confidence that the by-election will be peaceful.
Besides Sumra, and Wiper's Mawathe, there is Rameshchandra Gorasia, the owner of Taj Mall in Embakasi South Constituency, which was demolished last year.
Mr Gorasia is riding on sympathy votes from some supporters after losing his mall, which the Government claimed was built on a road reserve.
Ramesh back again
Gorasia had unsuccessfully vied for the Nairobi senatorial position in the 2017 General Election.
Roseline Ochuka of MTP, Urbanus Kaveva (PNU), Augustine Kavindu (GCK), Samuel Masaki (FPK) and Zablon Minyonga (KNC) are also in the race.
Alexander Mulatya (MCC), Jairus Musyoka (GDDP), Enosh Nyakweba (KSC), Agnes Nyalita (TAK), Enock Nyaribari (RLP), Peter Ogeta (PDU) and Nyamwange Oigara (JFP) have also been listed as contestants by IEBC. [Michael Chepkwony]