The US firm will acquire Careem’s mobility, delivery and payments businesses across the Middle East.
The purchase, which will be made in convertible notes and cash, will be finalised in the first quarter of 2020.
Careem will become a wholly-owned subsidiary of Uber, and will operate as an independent company.
Uber said in a statement it will pay $1.7bn in convertible notes and $1.4bn in cash for the acquisition.
Careem co-founder and chief executive Mudassir Sheikha will lead the Careem business, upon closing.
“This is an important moment for Uber as we continue to expand the strength of our platform around the world,” Uber Chief Executive Dara Khosrowshahi said in a statement.
“Careem has played a key role in shaping the future of urban mobility across the Middle East, becoming one of the most successful start-ups in the region,” he said.
The announcement comes amid reports that Uber is preparing to list in the New York Stock Exchange in April