The nine-year deal is for the installation and maintenance of gas transmission and distribution networks across the country.
Work will include the delivery of new construction, emergency response and planned maintenance services.
The contract will commence early in the New Year.
Ian Tyler, Balfour Beatty Chief Executive, said: “The Bord Gais award represents a significant development for our international utilities business.
“We are delighted to make this commitment to the Irish market and to continue to build upon our strategy to develop our international capability in the power sector.
“CLG has a proven track record of creating essential utility infrastructure in Ireland and we look forward to working with them to deliver gas networks for the people of this country.”