This will involve the design and construction of a large commercial building and two residential buildings, all of which are in the North Zone of the development.
Construction will start in the later part of 2015 on buildings known on the project as S2, R3, and R6, with completion scheduled during 2017.
Carillion Chief Executive, Richard Howson, said: “I am delighted that Carillion has been selected by Argent to design and construct these prestigious new buildings at King’s Cross.
“This builds on the strong long-term relationship we have established with Argent that I believe reflects our reputation for high-standards of quality, value for money and sustainability.”