Construction will start later this month on the site in Swindon and the fast-track job is due to be built in just seven months.
The £23m project involves construction of an 800,000 sq ft distribution centre for B&Q with work scheduled for completion by April 2011.
McLaren won the job from client Gazeley Properties after beating competition from Volker Fitzpatrick and Bowmer & Kirkland.
McLaren chairman Kevin Taylor said: “This is a significant win which reinforces our position as a leading contractor in the distribution centre market.
“The Swindon project is the latest success from our long-running association with Gazeley.”