The drinks giant currently uses four networks around the world, including Carat in the UK.
Diageo will handle the process itself with "a closed shortlist of agencies". Industry sources said all the main agency groups, including WPP, Omnicom and Carat’s owner, Dentsu Aegis Network, are likely to be approached.
The company, which owns brands including Guinness, Johnnie Walker and Smirnoff, is on a drive to cut costs across the business and is expected to reduce the number of media agencies that it uses. However, it is not clear if Diageo will consider consolidating all its planning and buying into a single network. The review is expected to finish by early 2017.
Diageo said: "This review is about ensuring we are set up for the future and have the right agencies that can deliver in the fast-paced, globally integrated digital media landscape."
In its half-year results, released in January, Diageo said it had cut marketing spend by 5% partly through "procurement savings" and other "efficiencies".
The company’s global procurement team is leading the review.
Diageo’s non-executive directors include Nicola Mendelsohn, Facebook’s vice-president of EMEA, and Lord Davies, a former chairman of Chime.