The contract is expected to be worth approximately £350m and might be extended for a further three years.
Carillion has already been providing facilities management services for Nationwide for nearly nine years.
Under the new contract, which started on 1st October 2016, Carillion is providing a range of hard and soft facilities management and workplace services for Nationwide's headquarters in Swindon, its 15 corporate offices, critical data centres and 700 retail branches throughout the UK.
Services include energy management, risk assurance, asset maintenance, capital works, front-of-house, security, grounds maintenance, mailroom management, porterage and cleaning.
Carillion chief executive Richard Howson said: "This demonstrates the success of our long-term partnership with Nationwide and our focus on differentiating Carillion by working collaboratively with customers to deliver an outstanding customer experience, using our expertise in whole-life property management and services.”