The news will be a bitter blow to the losing Connect Roads consortium of Balfour Beatty, Morrison and Carillion.
The project will complete the motorway network between Glasgow and Edinburgh by upgrading the A8 Baillieston to Newhouse.
It also includes work to improve the Raith Interchange and widening key sections of the M8, M73 and M74.
Transport Minister Keith Brown said: “The M74 Completion generated 900 construction jobs and we expect this project to be on a similar scale.
“There will also be opportunities for on the job training for apprentices and local employment.”
Work on the site is expected to begin late this year and the project is currently on track to be completed by Spring 2017.
Earlier this year, Transport Scotland awarded a £3.1m groundworks contract to Forkers Ltd.
This was the first of a series of advance works planned for the scheme which is now complete, allowing advance utility diversions to be undertaken ahead of the main construction works.