The seven-year residential and corporate property contract with social landlord East Thames Group could eventually double in value as it includes a provision to extend to 15 years.
Interserve will deliver services to 13,000 properties across East London and Essex. The contract includes a framework option to allow neighbouring public sector bodies access to Interserve's services.
Interserve executive director Bruce Melizan said: "This strategic partnership further extends Interserve's intelligent approach to delivering support services. This opportunity with East Thames Group broadens our residential maintenance portfolio, and will allow us to support the charity in regenerating East London and Essex to create communities where people want to live."