TNT bought 90% of Circular Distributors, the free sheet and sample delivery firm in 2001.
According to TNT Post, the move means it is the only company, apart from Royal Mail, that has the resources to deliver both unaddressed and addressed items.
The company's UK chief executive, Nick Wells, said: "The re-brand is an exciting and positive step forward for both companies as well as being extremely logical."
The UK postal market was deregulated at the beginning of this year. Recent client wins for TNT Post include HBOS, Telewest and Lloyds-TSB.
TNT repositions mailing brands
TNT Post has announced a shake-up of its mail brands. The Dutch firm, formerly TPG, is merging its Circular Distributors and TNT Mail companies under the name TNT Post.
