Odhiambo is the replacement for Zedekiah Otieno, who left the club to replace Frank Ouna as KCB's head coach.
Odhiambo's move to take the vacant position came as the club readies to leave for Rwanda and participate in the Cecafa Kagame Cup tournament, which starts on July 7.
"Yes I am joining Gor Mahia but we are still negotiating some aspects of the contract that includes the years of stay," Odhiambo told Goal.
The development coincides with head coach Hassan Oktay's return to the country from his vacation.
Odhiambo's departure comes after Derrick Otanga and Kevin Omondi moved to KPL new side Wazito.
Odhiambo's move to Gor Mahia may also persuade midfielder Tobias Otieno to join the club, with the midfielder reportedly among the players K'Ogalo aim to sign ahead of next season.
Gor Mahia have regularly appointed former players as assistant coaches and Odhiambo's arrival would break that culture, since he has never played for the 18-time KPL champions.
He led Sony Sugar to a fifth-place finish in the KPL last season.