The new company, which will have a portfolio of more than 1,300 hotels across the world, will be co-chaired by Hubert Joly and Kurt Ritter, presidents and chief executives of Carlson and Rezidor respectively.
While the current legal status and ownership structure of both companies will remain, the Carlson Rezidor Hotel Group will be responsible for the global alignment and management of the brands, the development of revenue generation engines, global purchasing and people development.
Joly said going to the market as one was a 'natural step' for the two companies who have worked together over the past 17 years.
"We are leveraging the strengths of two great companies to create value for all our stakeholders," he said.
Ritter added: "The goal of this development is to generate more attractive financial returns for the owners and greater value for all shareholders, to be perceived by business partners around the world as one global hotel company, to offer more compelling and consistent value propositions to the guests, and to offer global career and development opportunities to the staff."
The new company will have a global reach of 80 countries and will manage hotel brands such as Park Plaza, Radisson, Radisson Blu, Hotel Missoni and Park Inn by Radisson.
Its aim is to generate an extra US$400m in additional revenue and increase its revpar by more than nine points by 2015 across the group.
Joly and Ritter have set up a global steering committee to oversee a number of new initiatives which include developing partnerships with travel intermediaries such as Carlson Wagonlit Travel; growing loyalty programme Club Carlson as well as managing a global sales team and working on aligning brands for consistency.
The company is also aiming to become the number one hospitality company to work for with the creation of a global people development programme.