The rebranding project was handled by Futurebrand and involved the Zain brand replacing Celtel in 14 African countries including Kenya, Madagascar, Malawi and Uganda.
Zain Group's chief executive, Dr. Saad Al Barrak, said the rebranding of Zain would bring the company's main African and Middle East operations under a "single, strong and unique identity.
"We believe the Zain brand provides an optimal platform upon which we can build a top 100 global brand with the ultimate goal of better serving our customers. It builds upon the success of our African operations and will propel the Zain Group towards becoming one of the top ten global mobile telecommunications companies by 2011."
Coinciding with the launch of its new identity across Africa, Zain has also announced the creation of the world's first cross-continental borderless network, extending and linking its 'One Network' service between Africa and the Middle East.
The service will be available to 500m people stretching from the west coast of Africa to the Persian Gulf, covering an area larger than the US.
Dr Al Barrak said: "This truly is a defining moment in the history of global telecommunications. The connecting of One Network across two continents demonstrates how under one brand, Zain is able to offer enhanced mobile telephony services."
The rebranding of Celtel comes less than a year after the Zain brand became the group's master corporate brand following its successful launch across Middle Eastern markets.