The Super Eagles defender who has been with the Blues since 2012 featured 26 times and scored a goal while on loan to Alanyaspor as they finished 12th in the Super Lig.
The player will be expected to make his debut for the Apaches when they clash with Akhisar Belediyespor in Sunday’s Turkish Topflight encounter.
The former Middlesbrough star took to the social media to relish his return to the club he last featured for in the 2015/2016 season.
“God is Faithful. Happy to have renewed my contract with Chelsea until 2020 and also good to be back to Kasimpasa for one year,” Omeruo posted on Instagram.