The division will be led by Jeremy Hill, who will report to the chief executive of Starcom MediaVest, Iain Jacob. It will have specialist teams at both the Starcom MediaVest and Starcom Motive offices.
Hill says the new structure has been devised to take digital from being a niche fragmented service to one at the heart of communications planning.
He said: "In Starcom Digital, we have created a group of talented digital specialists who are also fully engaged with a brand's total communications requirements."
It will engage in planning and buying media across the internet, on interactive TV, mobile media and offer services in affiliate and search engine marketing.
Jacob said: "This is an important leap forward for our overall service proposition. Digital now plays an enormous role in consumers' lives. Our approach reflects this, elevating digital from a niche specialism into a core consideration in every plan for our clients."
Starcom Digital will handle its own clients as well as those held by the Starcom agencies. Among the clients on its books are Associated New Media, Telewest and Fiat.