The Governor of the State, Mr Abdulfatah Ahmed, said the underpass bridge was part of efforts to decongest traffic.
At the flag off ceremony, Governor Ahmed said the project, to be funded through the newly launched Kwara State Infrastructure Development fund (IF-K), is expected to be completed in 18 months.
The Governor, who toured the area on Wednesday, made his first stop at Geri Alimi roundabout in Ilorin in southwest Nigeria.