The agency was appointed following a three-way pitch and replaces incumbent Brave PR.
The account will be headed up by Trimedia board director James Wright and he will report into Indesit Company UK PR manager Emma Fountain.
Indesit Company includes brands including Hotpoint, Indesit and Cannon. It has operations in 32 countries and employs 17,000 people worldwide.
The agency is charged with targeting retailers, suppliers, internal audiences and local communities as part of the brief. Activity will include a corporate profile raising campaign to educate key stakeholders.