The 10-year deal marks a significant move by the Dubai-based airline to enhance its presence in cricket, adding to its position as Official Worldwide Partner to the International Cricket Council (ICC).
Emirates sponsored the 2012 World Twenty20 championships in Sri Lanka and it has held the naming rights to Durham's Chester-le-Street ground for the past three years.
Naming rights have become an increasingly popular way for sporting clubs, particularly football and cricket teams, to raise revenues.
Along with the renaming of the Old Trafford ground, the Emirates brand will also appear on Lancashire's Twenty20 kit as part of the deal.
Currently, Emirates has a presence in a number of sports, including football, cricket, horse racing and motor sport. It has sponsorship deals with Arsenal, Paris Saint-Germain and AC Milan football clubs, and is a global partner of F1 motorsport.
Old Trafford will host the third Ashes Test between England and Australia in August – the first time it has staged a Test since 2010.
Michael Cairns, chairman of Lancashire County Cricket club, said: "The intention to secure a naming rights partner was always on our list of objectives. However, it remained paramount that we secure a partner who was actively committed to cricket and its future, while at the same time had significant interest in Manchester and the North-West.
"The financial benefits of this deal are a component of our long-term strategy for commercial sustainability."
No financial details of the deal have been disclosed.Follow @johnreynolds10